Low Content Of Pt Research Articles

Bifunctional low-Pt content nanocatalysts supported on carbons functionalized with a Cu-organometallic compound: Tailoring of d-band center with high catalytic activity for electrochemical oxygen reactions

In this study, Vulcan XC-72 (C) and sewage sludge-derived biocarbon (SSB) are functionalized with mesitylcopper (Cu-mes) and implemented to produce the low-Pt content and thus low-cost (5 wt %) Pt/CCu-mes10, Pt/CCu-mes20, Pt/SSBCu-mes10, and Pt/SSBCu-mes20 nanocatalysts. This approach facilitates the generation of various functional groups along with the CuO and Cu2O phases. The nanocatalysts show the formation of the PtCu3 alloy, with the two first having an atomic fraction of Cu alloyed (XCu) of 55 and 67%, respectively. Pt/CCu-mes10 shows a comparable catalytic activity for the oxygen reduction reaction (ORR) before and after an accelerated degradation test (ADT) to 20 wt % Pt/C and 5 wt % Pt/C. It also shows the highest performance for the oxygen evolution reaction (OER), with remarkable electrochemical stability. The outstanding performance of Pt/CCu-mes10 is attributed to the presence of Cu-phases, its high degree of alloying and its d-band center which favorably promotes the adsorption of O-species and their further reaction. Specifically, the PtCu3 alloy promotes the kinetics of the reactions by modulating the electronic properties of Pt and creating dual active sites. Meanwhile, Pt/SSB demonstrates an encouraging performance for the reactions before ADT, with electrochemical parameters similar to those of 20 wt % Pt/C. However, its stability is poor, with low catalytic activity after ADT. Therefore, it is found that there is a significant effect of the electrochemical behavior of the carbon support on the performance and stability of the nanocatalysts. The potential application of Pt/CCu-mes10 in water splitting devices is identified.

Metal–organic framework derived synergistic carbon nanoarchitectures boost bifunctional electrocatalytic performances toward methanol oxidation and oxygen reduction in Pt-nanoparticles

Anchoring platinum (Pt) catalysts on appropriate supports through nanoarchitectonics is crucial in achieving a desirable high-performance electrode with low Pt content for direct methanol fuel cells (DMFCs). This manuscript presents the development of two low Pt-content electrocatalysts, Pt-NP@CNR and Pt-NP@CNF, synthesized from the same precursor MOF via two different pyrolysis techniques. Comparative experimental results demonstrate that the Pt-NP@CNR exhibits superior bifunctional activity for the Methanol Oxidation Reaction (MOR) and Oxygen Reduction Reaction (ORR) compared to Pt-NP@CNF. This enhanced performance is attributed to the synergistic effect between Pt-NPs and the high-surface area of porous carbon rod, which serves as the base material in Pt-NP@CNR. Pt-NP@CNR displays an impressive mass activity of 2.12 A mgPt−1, with exceptional cycle stability and minimal catalytic poisoning during MOR. Additionally, it achieves a remarkable E1/2 value of 0.71 V (vs. RHE), a maximum kinetic current density of approximately 2.13 mA cm−2, and low peroxide production, outperforming Pt-NP@CNF and commercial 10 % Pt/C in an alkaline medium. These findings demonstrate Pt-NP@CNR as a promising candidate for future commercializing of an efficient electrode for DMFCs due to its outstanding catalytic performance and versatile characteristics.

Sustainable chitosan hydrogen derived platinum/N-doped carbon aerogel for efficient oxygen reduction and hydrogen evolution reactions

Platinum (Pt)-based catalysts play a key role in electrocatalytic oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), and reducing Pt content and maintaining high electrocatalytic activity and durability are essential to its promoted application. In this work, low content of Pt (10.5 wt%) loaded defective N-doped carbon aerogel (Pt/D-NCA) was synthesized using natural protonated chitosan complexed chloride platinate ion (chitosan-PtCl62-) as precursor. Pt/D-NCA exhibits better ORR (half-wave potential of 0.89 V vs RHE) and HER (57 mV vs RHE overpotential at 100 mA/cm2) performance than commercial 20 wt% Pt/C, and can be used as efficient cathode for Zn-air battery and water spitting. The defective N-doped carbon support can effectively reduce energy barrier of Pt sites through interface effect to inducing high intrinsic ORR and HER catalytic activity. This work provides a sustainable route to synthesize low Pt consumption electrocatalyst through a sustainable and environmentally friendly pathway.

MOF-74 Derived Carbon-Stabilized Pt/Cu-PC-900 Nanoparticles: Ultra-low Pt Content and Improved Electrocatalytic Activity

Fuel cell technology is the best alternative to replace fossil fuels in the modern period. Platinum-based materials may function well as fuel cell electrodes because these can be employed as catalytic materials to carry out the infamous oxygen reduction process. In this respect, a copper-based metal-organic framework (Cu-MOF-74) was first created, to which ultralow content platinum nanoparticles (Pt/Cu-MOF-74) were added, and the structure was then studied using a variety of experimental approaches. After heating the MOF to 900 °C, Pt and Cu nanoparticles are incorporated into it to create a homogenized hybrid functional material, which is then pyrolyzed (Pt-Cu-PC-900). Compared to the 20% Pt/C catalyst available commercially, the Pt/Cu-PC-900 hybrid has shown superior ORR performance in terms of half-wave potential and limiting current density. This study emphasizes the value of nanoparticles with low content of Pt for potential large-scale commercial fuel cell applications.

Yolk-like Pt nanoparticles as cathode catalysts for low-Pt-loading proton-exchange membrane fuel cells

Currently, how to reduce the Pt loading in proton-exchange membrane fuel cell (PEMFC) is an urgent task for its practical application. Here, we propose a substrate engineering strategy of Pt catalysts to achieve low-Pt-loading PEMFC application, i.e., using the N-doped porous carbon (NC) with ultrahigh specific surface area (SSA) to trap Pt nanoparticle (NP). The egg-yolk-like Pt NP catalysts (Ptey/NC) have been synthesized successfully by using the strategy. The Ptey/NC not only possesses an ultrahigh SSA of 2271 m2/g and a relatively low-Pt content of 5.48 wt% but also shows better ORR activity and stability in acidic media than commercial 20% Pt/C. Using Ptey/NC as a cathode catalyst, the assembled PEMFC shows a high peak power density. At the ultralow-Ptey/NC loading of 0.03 mgPt/cm2, the Ptey/NC exhibits extremely high mass activity of 1.63 A/mgPt and 1.1 A/mgPt under 250 kPa and 150 kPa back pressure at 0.9 ViR-free in H2/O2 PEMFC, which are mainly attributed to the ultrahigh SSA plus low-Pt-content, rich mesopore structure, fully exposure of Pt (111), and the yolk-like special structure. DFT results further reveal that the interface effect between Pt NPs and NC significantly reduces the adsorption energy of oxygen species and, therefore, boosts its catalytic activity. This work provides a useful solution of using ultrahigh SSA catalyst plus low-Pt content to solve the low-Pt-loading problem, which would speed up the development of low-Pt-loading PEMFCs.

Electrochemically Dealloyed Cu–Pt Nanostructures for Oxygen Reduction and Formic Acid Oxidation

Surface engineering of catalysts by dealloying is a promising strategy to fine-tune the catalytic activity. Rational electrochemical surface engineering significantly improves the electrocatalytic performance. Herein, we demonstrate the synthesis of a surface-engineered CuxPty bimetallic electrocatalyst of low Pt content by solvothermal and subsequent electrochemical dealloying approaches for the electrocatalytic reduction of oxygen and oxidation of formic acid. The electrochemically dealloyed electrocatalysts have enhanced activity toward the oxygen reduction reaction and formic acid oxidation reaction (FAOR) due to the dealloying-induced increase in the electrochemically active surface area and lattice strain. Among the electrochemically dealloyed catalysts (Cu11Pt89, Cu17Pt83, and Cu23Pt77), Cu17Pt83 shows excellent ORR activity in acidic medium with an onset potential of 0.98 V. It delivers a limiting current density and mass specific activity of 5.4 mA/cm2 and 0.157 A/mgPt, respectively. The mass specific activity of Cu17Pt83 is 2–12 times higher than that of 20% Pt/C and monometallic Pt nanoparticles. The dealloying-induced lattice strain on Pt modifies the d-band structure. Such modification weakens the chemisorption of oxygenated species (OHads and OOHads) and improves the electron transfer kinetics. Among all dealloyed CuxPty catalysts, the low-Pt content Cu23Pt77 catalyst exhibits high FAOR activity. The Cu23Pt77 catalyst has good tolerance toward in situ generated CO, and the CO-stripping potential is significantly less positive compared to that of the other catalysts.

Efficient catalytic combustion of toluene at low temperature by tailoring surficial Pt0 and interfacial Pt-Al(OH)x species

SummaryExploring highly efficient and low-cost supported Pt catalysts is attractive for the application of volatile organic compounds (VOCs) combustion. Herein, efficient catalytic combustion of toluene at low temperature over Pt/γ-Al2O3 catalysts has been demonstrated by tailoring active Pt species spatially. Pt/γ-Al2O3 catalyst with low Pt-content (0.26 wt%) containing both interfacial Pt-Al(OH)x and surficial metallic Pt (Pt0) species exhibited super activity and water-resistant stability for toluene oxidation. The strong metal-support interaction located at the Al-OH-Pt interfaces elongated the Pt-O bond and contributed to the oxidation of toluene. Meanwhile, the OH group at the Al-OH-Pt interfaces had the strongest adsorption and activation capability for toluene and the derived intermediate species were subsequently oxidized by oxygen species activated by surficial Pt0 to yield carbon dioxide and water. This work initiated an inspiring sight to the design of active Pt species for the VOCs combustion.

Impact of Carbon Support Structure on the Durability of PtCo Electrocatalysts

High performing, low-Pt content fuel cell membrane electrode assemblies (MEAs) are critical to the economic viability of proton exchange membrane fuel cells (PEMFCs) for the transportation industry. Considerable research has been conducted to reduce the Pt content in fuel cells, leading to the development of transition metal alloys, such as Platinum-Cobalt (PtCo). The degree of degradation of PtCo catalysts can be impacted by not only the composition and morphology of the catalyst particle itself, but also its interactions with the carbon support. In this study several low-PtCo MEAs were fabricated, with various combinations of porous and solid carbon cathode catalyst supports. The MEAs were subjected to an accelerated stress test (AST), and the catalyst degradation characterized using electrochemical, X-ray scattering, and electron microscopy techniques. Porous supports retain more of their electrochemically-active surface area (ECSA) and demonstrate higher performance after the AST. This is believed to be due to the ability of the porous supports to trap the metal particles within the pores, slowing their dissolution/precipitation, and agglomeration. However porous supports also exhibit greater increases in transport resistance probably associated with enhanced Co leaching under the AST conditions.

Structure evolution and enhanced electrical performance for BiScO3–Bi(Ni1/2Zr1/2)O3–PbTiO3 solid solutions near the morphotropic phase boundary

In this work, the Bi(Me)O3–PbTiO3-type (1-x-y)BiScO3-xBi(Ni1/2Zr1/2)O3-yPbTiO3 (BS-xBNZ-yPT) ternary piezoelectric ceramics have been prepared with x ≤ 0.075 by the traditional solid-state reaction methods. For compositions with x > 0.100, the Curie temperature (Tc) will reduce below 400 °C. X-ray powder diffraction results demonstrate the system a single perovskite phase structure. Analyzed the phase structure evolutions, it can be found the MPB of this BS-xBNZ-yPT ternary solid solutions shifts to the low PT content regions with the increasing BNZ content. Dielectric diffuse behaviour in this system may result from the production of polar nanodomains by the introduction of BNZ. The piezoelectric performance is enhanced with only a little decrease in Tc by the introduction of small content BNZ. The most promising composition BS-0.025BNZ-0.635PT exhibits the piezoelectric constant d33 of 480 pC/N, planar electromechanical coupling coefficients kp of 58.2%, and Curie temperature Tc of 439 °C, respectively. The unipolar strain was found up to 0.233% with the small strain hysteresis of 11.4%. All these properties together with the good thermal stability indicate the BS-xBNZ-yPT ceramics potential candidates for high temperature piezoelectric actuator application.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

Surface Functionalization of Ordered Mesoporous Hollow Carbon Spheres with Ru Organometallic Compounds as Supports of Low-Pt Content Nanocatalysts for Alkaline Hydrogen and Oxygen Evolution Reactions

AbstractHerein, we report a methodology that leads to the formation of Ru metallic sites, followed by the development and anchorage of Pt-Ru alloyed nanoparticles on the surface of Ordered Mesoporous Hollow Carbon Spheres (OMHCS). Along with the Ru sites, it is demonstrated that the functionalization promotes the formation of functional groups on the surface of the OMHCS. In a first stage, OMHCS are functionalized with the [(η6-C6H5OCH2CH2OH)RuCl2]2 (Ru-dim) and [(η6-C6H4CH(CH3)2CH3)RuCl2]2 (Ru-cym) organometallic compounds. Afterwards, Pt nanoparticles are dispersed by the microwave-assisted polyol method over the functionalized supports obtaining the low-metal content 5 wt. % Pt/OMHCSRu-dim and Pt/OMHCSRu-cym nanocatalysts. The degree of Ru alloyed is found to be around 35%. The low-Pt content Pt/OMHCSRu-cym and Pt/OMHCSRu-dim exhibit a higher catalytic activity for the Oxygen (OER) and the Hydrogen (HER) Evolution Reactions than the Pt/C benchmark and the Pt/OMHCS nanocatalysts. The overpotential for the OER at 10 mA cm-2 (ηOER) is 300 mV and 210 mV smaller at Pt/OMHCSRu-cym and Pt/OMHCSRu-dim compared to Pt/C, respectively. The corresponding values of the HER at -10 mA cm-2 (ηHER) are 14 and 18 mV smaller, respectively. The high catalytic activity of Pt/OMHCSRu-cym and Pt/OMHCSRu-dim has been attributed in part to the presence of Ru0 and RuO2 species from organometallic functionalization, and the modification of the d-valence band of Pt. Their high performance for the OER and the HER opens new lines of research for the design of nanocatalysts for alkaline electrochemical water splitting.

Impact of Carbon Support Structure on the Durability of PtCo Electrocatalysts

High performing, low-Pt content fuel cell membrane electrode assemblies (MEAs) are critical to the economic viability of proton exchange membrane fuel cells (PEMFCs) for the transportation industry. Considerable research has been conducted to reduce the Pt content in fuel cells, leading to the development of transition metal alloys, such as Platinum-Cobalt (PtCo). The degree of degradation of PtCo catalysts can be impacted by the catalyst metal itself and its interactions with the carbon support. Several low-loaded PtCo MEAs were fabricated, with various combinations of porous and solid carbon cathode catalyst supports. The MEAs were subjected to an accelerated stress test (AST), and the catalyst degradation characterized using electrochemical, X-ray scattering, and electron microscopy techniques. Porous supports retain more of their electrochemically-active surface area (ECSA) and demonstrate higher performance after the AST. This is believed to be due to the ability of the porous supports to trap the metal particles within the pores, slowing their dissolution/precipitation, and agglomeration.

Developing efficient catalysts for the OER and ORR using a combination of Co, Ni, and Pt oxides along with graphene nanoribbons and NiCo2O4

The present work shows the development of efficient electrocatalysts for OER and ORR based on the combination of Ni and Co oxides with or without NiCo2O4, blended with or without graphene nanoribbons (GNRs) and composed of low content of Pt.

Hydroxyapatite-Supported Low-Content Pt Catalysts for Efficient Removal of Formaldehyde at Room Temperature.

Indoor environmental quality directly affects the life quality and health of human beings, and therefore, it is highly vital to eliminate the volatile organic compounds especially formaldehyde (HCHO), which is regarded as one of the most common harmful pollutants in indoor air. Hydroxyapatite (HAP)-supported Pt (Pt/HAP) catalysts with a low content of Pt (0.2 wt %) obtained via hydrothermal and chemical reduction processes could effectively remove gaseous HCHO from the indoor environment at room temperature. The influence of modifier in the preparation on the catalyst activity was investigated. The HAP and HAP modified by sodium citrate and hexamethylenetetramine-supported 0.2 wt % Pt could completely decompose HCHO into CO2 and water, while HAP modified by sodium dodecyl-sulfate-supported Pt removed HCHO primarily via adsorption. The HAP modified by the sodium citrate catalyst exhibited superior catalytic performance of HCHO compared to the HAP and HAP modified by hexamethylenetetramine and sodium dodecyl-sulfate-supported Pt catalysts, which was mainly because of its higher surface Ca/P ratio providing more Lewis acidic sites (Ca2+) for co-operational capture of HCHO molecules and a larger amount of active oxygen species. Our results indicate that an optimized combination of functional supports and low-content noble metal nanoparticles could be a route to fabricate effective room-temperature catalysts for potential application in indoor air purification.

Cu5Pt Dodecahedra with Low-Pt Content: Facile Synthesis and Outstanding Formic Acid Electrooxidation.

Tailoring composition and structure are significantly important to improve the utilization and optimize the performance of the precious Pt catalyst toward various reactions, which greatly relies on the feasible synthesis approach. Herein, we demonstrate that Cu-rich Cu5Pt alloys with unique excavated dodecahedral frame-like structure (Cu5Pt nanoframes) can be synthesized via simply adjusting the amounts of salt precursors and surfactants under hydrothermal conditions. It is established that the presence of hexamethylenetetramine and cetyltrimethylammonium bromide, as well as the selection of a proper Pt/Cu ratio are key for the acquisition of the target product. The immediate appeal of this material stems from frame-like architecture and ultralow Pt content involved, which can be used to greatly improve the utilization efficiency of Pt atoms. When benchmarked against commercial catalysts, the developed Cu5Pt nanostructures display superior electrocatalytic performance toward formic acid oxidation, owing to unique electronic effect and ensemble effect. This work elucidates a promising methodology for the synthesis of Pt-based nanostructures while highlights the significance of composition and structure in electrocatalysis.

Lead titanate-induced abnormal ferroelectric/antiferroelectric phase transitions in Pb(Lu0.5Nb0.5)O3 solid solutions

The development of bulk materials with ferroelectric/antiferroelectric (FE/AFE) phase transitions is of importance for meeting the needs of advanced electronic equipment. Here, we report a (1 − x)Pb(Lu0.5Nb0.5)O3-xPbTiO3 (abbreviated as PLNT100x) system, which shows a particular FE/AFE-like phase transition. A partial phase diagram with low PT content was delimited on the basis of the X-ray diffraction, differential scanning calorimeter, second harmonic generation, ferroelectric hysteresis loops and first-order reversal curve (FORC) methods. The intermediate phase showed AFE hysteresis loops may stem from the weakly polar to the polar phase during electrical poling and the lowering long-range ordering degree. It is a guideline to modulate the electric properties of PLNT AFE system such as Curie temperature, energy storage density and pyroelectric properties, by means of the control of composition.

Unusual strain effect of a Pt-based L10 face-centered tetragonal core in core/shell nanoparticles for the oxygen reduction reaction.

Nanoparticles with a low-Pt content core and a few-layer thick Pt skin are attractive catalysts toward the oxygen reduction reaction (ORR) not only for their low cost, but also because their activity can be enhanced by judiciously choosing the core alloy. Achieving the optimal ORR performance would require fine tuning of the core composition and structure. Previous work studying the enhancement effects has primarily focused on core alloys with a cubic structure, (i.e. disordered alloy or L12 ordered structure) which limits the tuning to composition alone. In this work, using ab initio calculations, we have systemically investigated a new class of Pt0.5M0.5 (M = V, Cr, Fe, Co, Ni and Cu) core alloy that has a face-centered tetragonal L10 intermetallic structure. We have calculated the adsorption energies of O, OH and OOH on various Pt skins and the underlying tetragonally structured alloys, which allows us to not only predict the optimal number of pure Pt skin layers but also tune the activity of the catalysts toward the peak of the ORR volcano plot. More importantly, using adsorption energies on intermediate structures, we are able to decompose the enhancement factor into the ligand, normal and shear strain effects, and reveal the significant contribution of the shear strain that is only possible with a tetragonal core but not a cubic one. Our results point to a new direction in designing tetragonally structured intermetallic core-shell nanoparticles for ORR applications.

Cobalt oxyhydroxide and carbon dots modified by platinum as superior electrocatalyst for methanol oxidation

The engineering of electrocatalysts with high performance for methanol oxidation reaction (MOR) is of great urgency for the development of direct methanol fuel cells (DMFCs). Here, we designed and fabricated cobalt oxyhydroxide and carbon dots modified by platinum (Pt-CoOOH-CDs/C) hybrids with low content of Pt (13 wt%) as electrocatalyst, which exhibit high activity (856.3 mA·mg−1Pt), stability (3 h) and better anti-poisoning ability for MOR. The Pt-CoOOH-CDs/C was synthesized by precipitate method followed with photochemical deposition. In the catalytic system, the Pt nanoparticles serve as the active center toward MOR, CoOOH-CDs use as the co-catalyst to oxidize CO-like poisonous species to CO2 on neighbouring Pt sites, and the cost-efficient carbon black enhances the conductivity for the system. The cost-efficient Pt-CoOOH-CDs/C system with improved kinetics for anodic methanol oxidation has promising application in alkaline DMFCs.

A New Strategy for Outstanding Performance and Durability in Acidic Fuel Cells: A Small Amount Pt Anchored on Fe, N co‐Doped Graphene Nanoplatelets

AbstractDevelopment of cost‐effective and efficient electrocatalysts for the oxygen reduction reaction (ORR) is one of the most important topics in the polymer electrolyte membrane fuel cells (PEMFCs). Herein, we suggested the enhanced electrochemical catalyst with nanoscale platinum anchored on iron (Fe) and nitrogen (N) co‐doped graphene nanoplatelets (Pt/FeN‐GnPs) with low content of Pt. The nanoscale platinum particles are uniformly anchored on the surface of FeN‐GnPs and result in excellent oxygen reduction activity and stability in acidic media. The fascinating interaction between Pt particles and FeN−GnPs substrate contributed to advanced oxygen reduction activity, outstanding cell performance, and remarkable high stability for acidic PEM fuel cells.

Significantly enhanced electrocatalytic activity of Au25 clusters by single platinum atom doping

The search for highly active catalysts with low-Pt content to advance the commercialization of fuel cells is continuing to receive ample attention. Herein, we report that by doping a single Pt atom into Au25 to form Pt1Au24 nanoclusters, the electrocatalytic activity for the direct formic acid oxidation (FAO) to carbon dioxide is enhanced significantly. The mass activity of Pt1Au24 (3.7 A mgPt+Au−1) is nearly 12 and 34 times greater than that of Pt nanoclusters and the commercial Pt/C catalyst, respectively. Density functional theory (DFT) calculations and potential-dependent thermodynamic analyses provide fundamental insights into the reaction mechanism illustrating that FAO proceeds through the carboxyl (COOH) intermediate on Pt1Au24. The present study not only develops a novel class of single-Pt atom doped Au nanocluster electrocatalysts for fuel cells with high utilization of Pt, but also provides insight into the mechanism of FAO on Pt-doped Au nanoclusters. Moreover, this study begins to shed light on the structure-activity relationship and helps to provide a strategy to design new catalysts by tuning their catalytic properties at the atomic level.