Browsing by Author "Liu, Jie"

Perovskite photovoltaics has attracted tremendous attention recently due to the advance in the device performance. However, it is still challenging to effectively commercialize the perovskite technology due to several issues including current-voltage hysteresis, stability, complicated device architectures, etc. In this dissertation, we use the additive to tailor the properties of the functional layers in perovskite photovoltaic devices, aiming to engineer the interface, film morphology, carrier dynamics and film crystallization process. By using the additive engineering approaches, our goal is to achieve high-performance perovskite photovoltaics with reduced hysteresis, improved stability, versatile processing methods and simplified device architectures.

Perovskite solar cells usually employ p-i-n device architectures and TiO2 is a typical n-type semiconductor widely used in perovskite solar cells. However, perovskite/TiO2 interface is not preferable for the photo-excited carrier collection due to the energy band misalignment, conductivity mismatch, etc. In chapter 2, additive was used to tailor the properties of TiO2 and enable improved interface for perovskite solar cells. With Nb5+ as additive in TiO2, the conductivity of TiO2 and interface band alignment were simultaneously improved. Consequently, high-performance perovskite solar cells were successfully obtained with reduced hysteresis by using the Nb-TiO2.

In addition to the interface, we explored the impact of morphology and carrier dynamics of perovskite films on solar cell performance. In chapter 3, NH4SCN and PbI2 were used as additives to tune the morphology and charge carrier dynamics of perovskite films. Using NH4SCN additive could significantly enlarge the grain size of the polymorph perovskite films while using PbI2 additive could increase charge carrier lifetime of perovskite films. It was found that the open-circuit voltage and fill factor of perovskite photovoltaics were correlative with charge carrier lifetime while short-circuit current density of perovskite photovoltaics were correlative with grain sizes. Using both PbI2 and NH4SCN simultaneously could synergistically improve the quality of perovskite films and performance of perovskite solar cells.

Based on the understanding from chapter 3, a room-temperature process was developed to deposit high-quality perovskite films by using PbI2 and methylammonium thiocyanate (MASCN) as additives in chapter 4. Due to the synergistic effects of the additives, room-temperature-processed perovskite films with micron-size grains and microsecond-range carrier lifetime were successfully obtained for high-performance devices. More importantly, we established the correlation between the crystal grain size in resultant perovskite films and the precursor aggregate size in precursor solutions. The correlation suggested that the perovskite grain sizes from solution process depended on the precursor aggregate sizes.

Following the understanding built in chapter 3, we used the additive engineering method to impact the performance of ETL-free perovskite solar cells. In chapter 5, we found out that the photo-excited carrier injection at the interface was significantly inhibited without the assistance of an ETL, which would compromise the collection of the photo-excited carriers. By using PbI2 as additive to tune the carrier lifetimes in perovskite films, it was found out that increased carrier lifetimes in perovskite films could effectively counterbalance the inferior interface without ETLs and enabled high performance for ETL-free perovskite solar cells. By using perovskite with microsecond carrier lifetime, ETL-free perovskite solar cells were successfully realized with performance comparable to that of ETL-containing perovskite devices. Such results offer the opportunity for the perovskite devices with simplified device architecture.

The development of electronic textiles, which have many potential healthcare and consumer applications, is currently limited by a lack of energy storage that can be effectively incorporated into such devices while having sufficient energy density, power density, and durability to perform well. The overall goal of this work was to improve the energy density and potential for use in electronic textile applications of a nanostructured composite of few-walled carbon nanotubes, manganese oxide, and reduced graphene oxide. Two approaches towards improving the desired properties by controlling the macroscopic structure of the composite were pursued: one, to make fiber or wire-shaped electrodes via wet-spinning in aqueous chitosan solutions (10% acetic acid), and the other, to make composite films with controlled porous structures using nitrocellulose as a sacrificial filler material. Both approaches yielded the desired macroscopic structures. The composite fibers were non-conductive due to the insulating nature of manganese oxide and its positioning on the surface of the fibers. Composite fibers of few-walled carbon nanotubes and reduced graphene oxide made by the same method were found to have good volumetric capacity, rate capability, stability and flexibility. Nonintuitively, electrochemical performance of composite films declined with increasing porosity due to a decrease in conductivity, highlighting the importance of balancing the interplay between properties important to device performance when designing controlled structures of complex materials.

The  first  chapter  introduces  the  background  about  energy  storage  and  lithium   ion  battery.  The  concepts  of  graphene,  carbon  nanotube,  and  carbon  aerogel  were   covered  as  well.  Then  powder-­based  metal  oxide-­carbon  composite  materials  and   binder-­free  CNT-­metal  oxide  films  for  lithium  storage  applications  were  further   elaborated.  Finally,  the  significance  of  our  research  was  summarized.  

The  second  chapter  is  about  freestanding  and  highly  conductive   Fe3O4/Graphene/CNT  film  as  lithium-­ion  battery  anodes.  Iron  oxide  is  intensively   studied  as  a  lithium-ion  battery  anode  material  due  to  its  high  theoretical  specific   capacity,  but  it  has  low  conductivity  and  poor  cycling  performance.  Herein,  we  present   the  design  of  freestanding  Fe3O4/graphene/Carbon  nanotube  film  via  in-­‐‑situ  growth  by   solvothermal  reaction,  vacuum  filtration  and  annealing  methods.  The  film  had  a  sheet   resistance  of  23  Ω/☐  and  a  BET  surface  area  of  132  m2/g.  The  synergistic  effect  of   graphene  and  CNTs  provide  a  flexible  matrix  to  accommodate  the  volume  change  of   metal  oxide  in  lithium  ion  batteries  application.  This  lightweight  film  was  tested  without   using  a  current  collector,  binder  and  conducting  additives,  eliminating  unnecessary   weight  in  the  overall  devices.  The  film  shows  excellent  cyclic  performances,  and  stable   rate  capability.  The  specific  capacity  retained  803  mAh/g  at  the  rate  of  200  mA/g  after  50   cycles.  This  method  demonstrated  a  promising  path  for  flexible  energy  storage  devices.

The  third  chapter  discusses  facile  synthesis  of  three‑dimensional  TiO2/carbon  co-­aerogel  nanostructures  and  their  applications  for  energy  storage.  In  the  field  of  energy   storage,  it  is  important  to  design  new  materials  and  understand  the  fundamental   principles  of  the  electrode  structure.  Facile  synthesis  of  TiO2/carbon  co-aerogel  material   via  a  sol-­gel  method  was  discussed.  This  new  material  was  composed  of  a  3-­D   interconnected  network  of  TiO2  and  carbon  aerogel.  TEM,  SEM,  XRD,  BET  SA,  and   electrochemistry  measurements  were  discussed.  With  an  operating  voltage  between  0.05   and  3.00  V,  the  discharge  capacity  was  ~400  mAh/g  at  168  mA/g  current  density.  

Energy storage systems are critically important for many areas in modern society including consumer electronics, transportation and renewable energy production. This dissertation summarizes our efforts on improving the performance metrics of energy storage and conversion devices through rational design and fabrication of hybrid nanomaterial systems.

This dissertation is divided into five sections. The first section (chapter 2) describes comparison of graphene and carbon nanotubes (CNTs) on improving the specific capacitance of MnO2. We show that CNTs provided better performance when used as ultrathin electrodes but they both show similar performance with rapid MnO2 specific capacitance decrease as electrodes become thicker. We further designed ternary composite electrodes consisting of CNTs, graphene and MnO2 to improve thick electrode performance (chapter 3). We demonstrate that these electrodes were flexible and mechanically strong, had high electrical conductivity and delivered much higher capacity than electrodes made without CNTs.

Chapter 4 describes assembly of flexible asymmetric supercapacitors using a graphene/MnO2/CNTs flexible film as the positive electrode and an activated carbon/CNTs flexible film as the negative electrode. The devices were assembled using roll-up approach and can operate safely with 2 V in aqueous electrolytes. The major advantage of these devices is that they can deliver much higher energy under high power conditions compared with those designed by previous studies, reaching a specific energy of 24 Wh/kg at a power density of 7.8 kW/kg.

Chapter 5 describes our approach to improve the energy and power densities of nickel hydroxides for supercapacitors. This was done by assembling CNTs with Co-Ni hydroxides/graphene nanohybrids as freestanding electrodes. The assembled electrodes have dramatically improved performance metrics under practically relevant mass loading densities (~6 mg/cm2), reaching a specific capacitance of 2360 F/g at 0.5 A/g and 2030 F/g even at 20 A/g (~86% retention).

Finally, we discuss our efforts on designing highly active electrocatalysts based on winged nanotubes for oxygen reduction reactions (ORR). The winged nanotubes were prepared through controlled oxidization and exfoliation of stacked-cup nanotubes. When doped with nitrogen, they exhibited strong activity toward catalyzing ORR through the four-electron pathway with excellent stability and methanol/carbon monoxide tolerance owning to their unique carbon structure.

The chemical industry depends on heterogeneous thermocatalytic processes to satisfy the ever-increasing demand for fuels and fertilizers. High temperatures and high pressures are generally required to accelerate chemical transformations and operate practical rates. These harsh conditions, however, lead to huge energy consumption and other side effects, such as the lifetime of catalysts and parasitic formation of by-products. Light is used as an alternative energy input to drive chemical reactions on semiconducting photocatalysts, but the slow reaction rates and insufficient control of product selectivity hinder wide adaptation of photocatalysis. Plasmonic metal nanoparticles have been recently proposed as a new type of catalysts with photoactivities. As already been widely used in thermocatalytic reactions, the strong light absorption capability from excitation of localized surface plasmon resonance (LSPR) of plasmonic catalysts could combine light and thermal energy to work cooperatively in enhancing rates of chemical reactions. This dissertation summarizes our efforts aiming to design plasmonic catalysts with high efficiency and high product selectivity. The catalytic properties of synthesized rhodium (Rh) and ruthenium (Ru) catalysts are investigated in two model reactions, carbon dioxide (CO2) hydrogenation and ammonia (NH3) synthesis.

Chapter 2 describes the development of slow-injection polyol methods to synthesize monodispersed Rh nanocubes with tunable size and resonant energy. The wide size tunability of slow-injection methods allows for the red-shift of resonant wavelength of small Rh nanostructures, which are in the deep ultraviolet (UV) region, to more accessible and practical near-UV and visible regions by increasing the size of Rh nanocubes.

Chapter 3 focuses on the product selectivity of plasmonic Rh nanocubes in CO2 hydrogenation. Rh nanocubes supported on aluminum oxide (Al2O3) nanoparticles equally produce methane (CH4) and carbon monoxide (CO) in pure thermal conditions. Under illumination of UV and blue light, the rate of CH4 production is significantly enhanced, and almost exclusive CH4 production is observed. This photo-selectivity can be attributed to selective activation of specific reaction intermediate by photo-generated hot electrons among competing reaction pathways.

Chapter 4 describes the effects of catalyst support and morphology of plasmonic Rh nanostructures on the catalytic activities in plasmon-enhanced CO2 hydrogenation. Significant improvements of reaction rates are observed by switching to reducible titanium oxide (TiO2) support and shrinking the size of Rh nanostructures. The enhancement of reaction rates by light can be partially attributed to local heating of catalyst bed.

Chapter 5 focuses on the catalytic activities of Ru-based catalysts for NH3 synthesis under light illumination. Photo-enhanced NH3 production, which highly depends on the size, support, and promoter of catalysts, is observed.

Chapter 6 discusses conclusion and future directions of this project. Molecular level insights of plasmon-enhanced catalysis are highly desired for both fundamental research and practical applications.

Energy storage technologies are receiving a great deal of attention today due to their potentials to expedite current efforts to make a low carbon energy future possible. Electrochemical energy storage systems – supercapacitors and batteries – have demonstrated their ability to bring multiple benefits as a viable and complementary technology for making renewable energy resources more available to people. Lithium-ion batteries, as a mature electrochemical energy storage technology, currently dominate the portable electronics market, and are continuously trying to expand into new markets with the global trend towards electric vehicles and smart girds. However, their high cost associated with performance improvement prevents them from penetrating into these new applications. Therefore, advances in new materials that could be made available in large quantities at low cost, while satisfying various industry requirements and being safe and durable, are extremely important in order to overcome the above limitations. Improving the performance metrics of electrochemical energy storage devices through rational design of carbon materials has been the major focus of the research presented in this dissertation. A variety of carbon materials including activated carbon, carbon nanotubes, graphene, and carbon aerogel have been investigated. However, as no material is perfect, each having its own advantages and disadvantages, it is unlikely that a single material could provide a complete solution to problems of the existing electrochemical energy storage systems.

This dissertation proposes design strategies that lead to significant improvements in the performance of electrochemical energy storage devices by appropriate choice of carbon materials and further development of novel electrodes. Chapter 2 describes an approach of designing a two-dimensional carbon thin film electrode with a double-layered structure composed of polyetheretherketone-derived microporous carbon and graphene. Such layered combination of the two carbons shows synergistic properties by complementing each other, therefore creating a highly porous conductive carbon films for supercapacitors. Chapters 3 through 6 highlight a novel method for developing a special type of highly conductive and porous three-dimensional materials, which are polymer-cross-linked carbon aerogels, namely carbon x-aerogels. These carbon x-aerogels constitute the major contributions of this dissertation. Carbon x-aerogels are designed to solve problems with conventional carbon aerogels. They are not only porous and conductive, but also mechanically robust with high compressibility with fast recovery. This multi functionality makes them promising for developing high-energy-density supercapacitors (Chapter 3) and next-generation rechargeable batteries that will eventually power the beyond current lithium-ion technology, such as lithium-oxygen (Chapter 4) and lithium-sulfur batteries (Chapter 5). Chapter 6 describes another potential application of carbon x-aerogels beyond its utilizations in electrochemical energy storage devices, which is its application as novel electrode materials for capacitive deionization that can make the current water treatment technology more cost-effective. In conclusion, the most important achievement in this dissertation is the successful development of carbon x-aerogels, which currently is laying the groundwork for future research on materials design and which ultimately will provide practical solutions to challenges in energy storage technology and beyond.

Single-walled carbon nanotubes (SWCNT) are unique, anthropogenic allotropes of nanoparticulate black carbon. As numerous industrial and commercial uses of SWCNT result the heavy expansion of production of this material, the release of SWCNT is likely to occur, increasing their level in air, water and soil. SWCNTs have been shown to cause adverse impact in organisms from direct exposure through ingestion or inhalation. In addition to direct exposure, SWCNT can also induce toxicity to organisms by indirect exposure such as adsorption of hydrophobic contaminants (HOCs). One unique property of SWCNT is the quantized nature of their electronic structure, which is dependent on the chiral wrapping angle of the sp2 hybridized graphene sheet that comprises the wall of each SWNT species. Using probe HOCs – one planar polycyclic aromatic hydrocarbon (PAH)14 C-naphthalene and one halogenated aromatic 14 C-hexachlorobenzene and purified conductive and semiconductive SWCNT species, my first study aimed at assessing the role of SWCNT electronic structure on HOC sorption. Despite their differences in electronic structures, the results indicated that overall the electronic structure does not influence the adsorption of HOCs. However, due to the large specific surface area, SWCNT have a general high affinity for HOCs. Upon release of SWCNT into aquatic environment, SWCNT have the potential to affect the distribution of organic contaminants by acting as strong sorbent.

A significant barrier to studying toxicity of SWCNT to animal models is the lack of in vivo techniques to track and quantify SWCNT for assessing their distribution, transport and bioaccumulation. The fluorescence resulting from the unique band gap of each species of semiconductive SWCNT allows the detection and quantification of a bulky SWCNT sample using near infrared fluorescence spectroscopy (NIRF). NIRF is highly sensitive to detect SWCNT in biological tissues due to the low fluorescence in the near infrared region from biological samples. Two exposure routes were investigated using NIRF: ingestion from dietary track using fathead minnow (FHM) fish model in an aquatic environment and inhalation through lung using mouse model. The SWCNT extraction conditions were optimized and validated using spike recovery experiments. SWCNT were extracted from fish tissues, intestine, and liver using ultrasonic extraction in 2% sodium deoxycholate1extraction. Proteinase K digestion was needed for dissolving mouse lung prior to SDC extraction. The quantification results showed that while SWCNT readily passed through fish dietary track with minimal partition into the lumen tissue and caused no acute toxicity; SWCNT was less mobile in respiratory system and was responsible for the lung-term pulmonary disease induced.

The fate, transport and bioaccumulation of SWCNT are essential information for risk assessment and making environmental regulations for nanomaterials. Currently the lack of standardized sensitive characterization and quantitative analytical methods for SWCNT determination at the current levels in the environment is one major barrier for evaluation of their real impact to the environment. NIRF is sensitive for environmental samples. However, this technique is not sensitive to all types of SWCNT. Metal catalysts are widely used in synthetic production of SWCNTs, leading to total metal content ranging from 5 - 30%. The metal: metal ratios and metal: carbon ratios of SWCNT are very distinctive from many geological materials. A metal fingerprinting approach was developed by monitoring the metal type and metal: metal ratios, along with elemental carbon content. SWCNT can be principally quantified using inductive coupled plasma mass spectrometry (ICP-MS). Metal content, metal: metal ratios, elemental carbon and metal: carbon ratios were analyzed for two aerosol matrices, the urban dust NIST SRM 1649b and aerosol collected at Duke University using three types of SWCNT: SG65 SWCNT, SG65i SWCNT and P2 SWCNT. Results demonstrated that the metal finger approach worked well with all aerosol matrices with detection limits near ng m-3. It worked best with elements that were less abundant in the background such as Co and Y. This method offers a robust and economic approach for application to occupational spaces for monitoring possible SWCNT release.

Applying a similar approach in sediment presents a significant challenge as background metals present in sediment complicates such analyses. To overcome these challenges, we have applied density gradient ultracentrifuge (DGU) to isolate and separate SWCNT in sediment extracts prior to both NIRF and ICP-MS analysis. Several types of SWCNTs (arc discharge, CoMoCat, and HiPCO) were spiked and subsequently extracted from estuarine sediments. SWCNTs were separated into different bands after DGU, primarily into two distinct horizons (one showed near infrared fluorescence, while the other did not). Two techniques,near-infrared spectroscopy (NIRF) and ICP-MS, were applied for quantitation of SWCNTs in these bands. Results indicate excellent separation of SWCNT from interferences in sediments. We have also discovered an apparent disconnect between the metal catalyst particles and SWCNT during density gradient ultracentrifuge separation. It is clear that the SWCNT (within the NIRF band) is not physically associated with metal catalyst. This result was further confirmed using single-particle ICP-MS. Although DGU separation seems to be an outstanding method for isolating SWCNT from aquatic sediment for analysis, our current findings indicate that metal fingerprints derived from residual catalyst may not be a good tracer for SWCNT occurrence and fate in marine sediments, as the associated metal catalyst particles in SWCNT preparations might be transported in different ways relative to the SWCNT.

Overall, my research explored several analytical techniques to detect and quantify SWCNTs at their relevant concentration in various environmental matrices. These techniques will provide essential information for evaluating the environmental impact based on SWCNTs fate, transport and bioaccumulation in the environment.

Background: In 2017, China launched the Urban and Rural Residents' Basic Medical Insurance program, with the primary goal of improving insurance benefits, particularly for those living in rural areas, and reducing rural-urban disparities. This study examined the impact of China’s Urban and Rural Residents' Basic Medical Insurance on the retirement decisions and labor market participation of individuals in rural areas aged 45 years and older. I hypothesized that the health insurance reform may increase the likelihood of retirement and reduce weekly working hours by alleviating their concerns about potential catastrophic medical expenditures in the future and motivating them to allocate more time towards managing their health conditions.Methods: To test this hypothesis, I used the nationally representative data from the China Health and Retirement Longitudinal Study, which comprises data from the waves conducted in 2011, 2013, 2015, and 2018. The final sample consisted of 6,536 rural participants aged 45 years and older who had complete data for outcome and control variables. The outcome variables examined in this study were retirement status, a binary variable that takes 1 if the participant is retired, and working hours per week, a continuous variable. This study controlled for individual-level variables including age, gender, marital status, education level, income, number of living children, number of living sons, and self-reported health, and city-level variables including GDP per capita and unemployment rate. To address potential endogeneity, this study employed the instrumental variable method, using whether the program was implemented before a given year as an instrument. Specifically, the Probit model with the IV as an independent variable was first implemented to estimate the probabilities of enrolling in the URRBMI. Subsequently, the fitted enrollment probability was included as an instrument for the endogenous variable along with exogenous covariates in a Two-stage Least-squares Regression. Results: In the final sample, 26.24% of the participants were in a retired status. The mean weekly working hours stood at 32.03 hours. The IV regression results indicated that the URRBMI increased the likelihood of retirement by 22.5% and led to a reduction of 13.51 hours in the working hours after adjusting for individual-level control variables and city-level control variables. The decrease in working hours was primarily driven by a decrease in labor supply among those who continue to work. Through heterogeneous analysis, I found that this behavioral shift could be primarily attributed to the reform's incentivization of individuals to allocate a greater portion of their time to healthcare management and its role in mitigating the probability of catastrophic health expenditure. Furthermore, I found suggestive evidence that after this reform individuals exhibited a 54% increased likelihood of engaging in self-employment and a 66% decreased likelihood of working off-farm. Conclusions: This study provided evidence that among those aged 45 and above in rural settings, the implementation of the URRBMI motivated them to retire earlier and reduced their working hours per week. Additionally, the URRBMI enhanced the likelihood of agricultural employment and self-employment, which is instrumental in curbing rural depopulation and fostering entrepreneurship within society.

With the rising level of CO2 in the atmosphere, methods capable of converting CO2 into useful fuels are urgently needed. The electrochemical CO2 reduction has gained significant interest recently due to its ability to use renewable energies. However, the poor stability of catalysts in electrochemical CO2 reduction limit its application in industry. Here we have developed a light-involving method to remove the surface carbonaceous species which are believed to poison the catalysts. By taking advantage of plasmonic properties of the copper catalyst, the stability of the catalysts has apparently improved.

Another problem in electrochemical CO2 reduction is the poor selectivity. One of the main reasons is the existence of the side reaction, hydrogen evolution reaction. Here we have developed a catalyst by dispersing atomic nickel on nitrogen-doped winged carbon nanotubes with the ability to suppress hydrogen evolution during CO2 reduction. The Faradaic Efficiency of CO reached 90% at -1.6 V vs. AgCl/Ag reference electrode while the efficiency of HER had been suppressed to less than 10% in the optimal reaction condition. By comparing with Ni NPs, the suppression of HER can be directly observed in LSV curve. It is suggested that this suppression may result from the lack of adjacent active sites for the Tafel mechanism in HER.

The solid-gas phase reactions, such as CO2 hydrogenation, the Fischer-Tropsh process, CO oxidation, and ammonia synthesis are one of the heterogenous catalytic reactions which have been emerged as a critical process in chemical and energy industries for a sustainable future. It needs a catalyst to change the chemical reaction pathway and enables the reaction to happen under milder condition. Metal catalysts supported on the metal oxide or unsupported metal crystallites have shown various catalytic behavior in different catalytic reactions. It can be divided into categories, catalysts with small sizes, such as single atoms, nanoclusters and nanoparticles, and also bulk catalysts. Bulk metal oxides or mixed oxides are widely used as heterogeneous catalysts in the current industry due to their ability for large-scale synthesis. However, the complex surface structures of metal oxides and mixed metal oxides, such as various oxidation states, oxygen vacancies, chemical nature of the active site (acid or base), are difficult to be characterized and developed by empirical methods. With the development of nanoscience and nanomaterials, nano-sized catalysts are well-studied. However, it lacks large-scale synthetic methods for practical use. To design catalysts for heterogeneous reactions, the Sabatier’s principle is used that the relationship of the catalytic activity and adsorption energies of reactants, products or intermediates is a volcano curve. To fit the volcano curve and predict the most optimal catalyst composition. The reaction mechanisms need to be studied and understood to determine the rate-limiting step. Based on that, better design of process and catalyst composition can be developed for efficiently producing a desirable product. In Chapter 2, the rate-limiting step for producing methanol in CO2 hydrogenation reaction under ambient pressure is to desorb methanol from the indium oxide surface. Therefore, we’ve designed a two-temperature process to use a photothermal effect to desorb methanol by quickly flipping the reaction temperature to a higher set temperature. In Chapter 3, the key to achieving high CO selectivity in CO2 hydrogenation reaction is to control the binding strength of reaction intermediate *CO. A one-step synthesis method, glycine-nitrate combustion was developed to synthesize a rhodium-based catalyst supported on high entropy oxide. The selectivity of this reaction can be tuned by changing the composition of elements in metal oxide support. In Chapter 4, the rate-limiting step of the ammonia decomposition reaction is desorbing N2. Following the same combustion synthesis method in Chapter 3, we used empirical experiments to determine the most optimal composition in bulk CoMo bicatalyst when Co/Mo molar ratio is at 6:1. And the same ammonia decomposition catalytic activity can be achieved compared to the noble ruthenium-based catalyst, just by increasing the mass of catalyst, which is accessible here. One variable to be tuned in the catalyst composition limits the enhancement of catalytic activity. However, multiple variables to be tuned at the same time is impractical to analyze data and conclude it by human-being. With the simple synthesis method that we’ve developed for synthesizing bulk catalysts. It’s promising and practical to provide training data for artificial intelligence to optimize the composition of earth-abundant catalysts to replace the noble metal catalyst in the future in the solid-gas phase reactions.