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While the role of crystal facets is well known in traditional heterogeneous catalysis, this effect has not yet been thoroughly studied in plasmon-assisted catalysis, where attention has primarily focused on plasmon-derived mechanisms. Here, we investigate plasmon-assisted electrocatalytic CO2 reduction using different shapes of plasmonic Au nanoparticles - nanocube (NC), rhombic dodecahedron (RD), and octahedron (OC) - exposing {100}, {110}, and {111} facets, respectively. Upon plasmon excitation, Au OCs doubled CO Faradaic efficiency (FECO) and tripled CO partial current density (jCO) compared to a dark condition, with NCs also improving under illumination. In contrast, Au RDs maintained consistent performance irrespective of light exposure, suggesting minimal influence of light on the reaction. Temperature experiments ruled out heat as the main factor to explain such differences. Atomistic simulations and electromagnetic modeling revealed higher hot carrier abundance and electric field enhancement on Au OCs and NCs than RDs. These effects now dominate the reaction landscape over the crystal facets, thus shifting the reaction sites when comparing dark and plasmon-activated processes. Plasmon-assisted H2 evolution reaction experiments also support these findings. The dominance of low-coordinated sites over facets in plasmonic catalysis suggests key insights for designing efficient photocatalysts for energy conversion and carbon neutralization. Crystal facets are known to be important in traditional heterogeneous catalysis, yet this effect has not been studied in plasmon-assisted catalysis. Here, the authors investigate the impact facets have on CO2 reduction using plasmonic Au NPs. [ABSTRACT FROM AUTHOR]

While the role of crystal facets is well known in traditional heterogeneous catalysis, this effect has not yet been thoroughly studied in plasmon-assisted catalysis, where attention has primarily focused on plasmon-derived mechanisms. Here, we investigate plasmon-assisted electrocatalytic CO2 reduction using different shapes of plasmonic Au nanoparticles - nanocube (NC), rhombic dodecahedron (RD), and octahedron (OC) - exposing {100}, {110}, and {111} facets, respectively. Upon plasmon excitation, Au OCs doubled CO Faradaic efficiency (FECO) and tripled CO partial current density (jCO) compared to a dark condition, with NCs also improving under illumination. In contrast, Au RDs maintained consistent performance irrespective of light exposure, suggesting minimal influence of light on the reaction. Temperature experiments ruled out heat as the main factor to explain such differences. Atomistic simulations and electromagnetic modeling revealed higher hot carrier abundance and electric field enhancement on Au OCs and NCs than RDs. These effects now dominate the reaction landscape over the crystal facets, thus shifting the reaction sites when comparing dark and plasmon-activated processes. Plasmon-assisted H2 evolution reaction experiments also support these findings. The dominance of low-coordinated sites over facets in plasmonic catalysis suggests key insights for designing efficient photocatalysts for energy conversion and carbon neutralization. Crystal facets are known to be important in traditional heterogeneous catalysis, yet this effect has not been studied in plasmon-assisted catalysis. Here, the authors investigate the impact facets have on CO2 reduction using plasmonic Au NPs. [ABSTRACT FROM AUTHOR]

Regulating the coordination environment of transition-metal based materials in the axial direction with heteroatoms has shown great potential in boosting the oxygen reduction reaction (ORR). The coordination configuration and the regulation method are pivotal and elusive. Here, we report a combined strategy of matrix-activization and controlled-induction to modify the CoN4 site by axial coordination of Co—S (Co1N4-S1), which was validated by the aberration-corrected electron microscopy and X-ray absorption fine structure analysis. The optimal Co1N4-S1 exhibits an excellent alkaline ORR activity, according to the half-wave potential (0.897 V vs. reversible hydrogen electrode (RHE)), Tafel slope (24.67 mV/dec), and kinetic current density. Moreover, the Co1N4-S1 based Zn-air battery displays a high power density of 187.55 mW/cm2 and an outstanding charge—discharge cycling stability for 160 h, demonstrating the promising application potential. Theoretical calculations indicate that the better regulation of CoN4 on electronic structure and thus the highly efficient ORR performance can be achieved by axial Co—S. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) in neutral media is of great practical importance for sustainable hydrogen production, but generally suffers from low activities, the cause of which has been a puzzle yet to be solved. Herein, by investigating the synergy between Ru single atoms (RuNC) and RuSex cluster compounds (RuSex) for HER using ab initio molecular dynamics, operando X-ray absorption spectroscopy, and operando surface-enhanced infrared absorption spectroscopy, we establish that the interfacial water governs neutral HER. The rigid interfacial water layer in neutral media would inhibit the transport of H2O*/OH* at the electrode/electrolyte interface of RuNC, but the RuSex can promote H2O*/OH* transport to increase the number of available H2O* on RuNC by disordering the interfacial water network. With the synergy of RuSex and RuNC, the resulting neutral HER performance in terms of mass-specific activity is 6.7 times higher than that of 20 wt.% Pt/C at overpotential of 100 mV. Understanding the slow kinetics of hydrogen evolution reaction in neutral media is of fundamental importance for the rational design of high-performance electrocatalysts for hydrogen energy. Here, by studying Ru single atom and RuSex cluster, the authors report how the rate of hydrogen evolution reaction activity in neutral media is governed by interfacial water. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of the carbonyl bond in α,β-unsaturated carbonyl compounds is rather challenging owing to the more feasible hydrogenation of ethylenic bond from both thermodynamic and kinetic aspects. Here, we demonstrate a facile emulsion-based molecule-nanoparticle self-assembly strategy for the atomic engineering of Ir species on three-dimensional CeO2 spheres (Ir1@CeO2). When applied to the hydrogenation of α,β-unsaturated aldehydes, Ir1@CeO2 catalyst remarkably exhibited ~ 100% selectivity towards unsaturated alcohols, whereas the formation of Ir nanoparticles on CeO2 drastically decreased the selectivity for unsaturated alcohols. Spectroscopic studies revealed that strong metal—support interactions triggered the charge transfer from Ir to CeO2, leading to the partial reduction of Ce4+ to Ce3+ along with the formation new Irδ+—O2−—Ce3+(OV) interfaces. The electrophilic atomic Ir species at the Irδ+—O2−—Ce3+ (OV) interfaces would therefore preferentially adsorb and facilitate hydrogenation of polar C=O bond to achieve exceptional selectivity. [ABSTRACT FROM AUTHOR]

In recent years, the isolated single-atom site (ISAS) catalysts have attracted much attention as they are cost-effective, can achieve 100% atom-utilization efficiency, and often display superior catalytic performance. Here, we developed a biomass-assisted pyrolysis-etching-activation (PEA) strategy to construct ISAS metal decorated on N and B co-doped porous carbon (ISAS M/NBPC, M = Co, Fe, or Ni) catalysts. This PEA strategy can be applied in the universal and large-scale preparation of ISAS catalysts. Interestingly, the ISAS M/NBPC (M = Co, Fe, or Ni) catalysts show multi-functional features and excellent catalytic activities. They can be used to conduct different types of catalytic reactions, such as O-silylation (OSI), oxidative dehydrogenation (ODH), and transfer hydrogenation (THG). In addition, we used the transfer hydrogenation of nitrobenzene as a typical reaction and revealed the difference between ISAS Co/NBPC and ISAS Co/NPC (N-doped porous carbon) catalysts by density functional theory (DFT) calculations, and which showed that the decreased barrier of the ratedetermining step and the low-lying potential energy diagram indicate that the catalytic activity is higher when ISAS Co/NBPC is used than that when ISAS Co/NPC is used. These results demonstrate that the catalytic performance can be effectively improved by adjusting the coordination environment around the ISAS. [ABSTRACT FROM AUTHOR]

Efficient electroreduction of CO2 into CO and other chemicals turns greenhouse gases into fuels and value-added chemicals, holding great promise for a closed carbon cycle and the alleviation of climate changes. However, there are still challenges in the large-scale application of CO2 electroreduction due to the sluggish kinetics. Herein we develop a self-assembly strategy to synthesize a highly efficient CO2 reduction electrocatalyst with atomically dispersed Ni-N4 active centers anchored on polymer-derived mesh-like N-doped carbon nanofibers (Ni-N4/NC). The Ni-N4/NC exhibits high selectivity for CO2 reduction reaction with CO Faradaic efficiency (CO FE) above 90% over a wide potential range from −0.6 to −1.0 V vs. RHE. The catalyst reaches a maximum CO FE up to 98.4% at −0.8 V with a TOF of 1.28 × 105 h−1 and Tafel slope of 113 mV·dec−1. The catalyst also exhibits remarkable stability, with little change in current density and CO FE over a 10-hour durability test at −0.8 V vs. RHE. This method provides a new route for the synthesis of highly efficient CO2 reduction electrocatalyst. [ABSTRACT FROM AUTHOR]

Structural reconstruction of nanomaterials offers a fantastic way to regulate the electronic structure of active sites and promote their catalytic activities. However, how to properly facilitate surface reconstruction to overcome large overpotential that stimulate the surface reconstruction has remained elusive. Herein, we adopt a facile approach to activate surface reconstruction on Ni(OH)2 by incorporating F anions to achieve electro-derived structural oxidation process and further boost its oxygen evolution reaction (OER) activity. Ex situ Raman and X-ray photoemission spectroscopy studies indicate that F ions incorporation facilitated surface reconstruction and promotes the original Ni(OH)2 transformed into a mesoporous and amorphous F-NiOOH layer during the electrochemical process. Density functional theory (DFT) calculation reveals that this self-reconstructed NiOOH induces a space-charge effect on the p-n junction interface, which not only promotes the absorption of intermediates species (*OH, *O, and *OOH) and charge-transfer process during catalysis, but also leads to a strong interaction of the p-n junction interface to stabilize the materials. This work opens up a new possibility to regulate the electronic structure of active sites and promote their catalytic activities. [ABSTRACT FROM AUTHOR]

In the field of electrolysis of water, the design and synthesis of catalysts over a wide pH range have attracted extensive attentions. In this paper, Co and N are co-introduced into the structural unit of tungsten disulfide (WS2), and the hydrogen evolution reaction (HER) performances of different WS2-based catalysts are theoretically predicted and systematically studied by density functional theory (DFT) calculations. With the guidance of DFT calculations, an evaporation-pyrolysis strategy is applied to prepare Co and N co-doped WS2 (Co,N-WS2) flower-like nanosheets, which exhibits excellent HER performance over a wide pH range. In addition, the DFT calculations show that the active sites in Co,N-WS2 have a good ability of hydrogen adsorption after the introduction of Co and N, suggesting that such a co-doping system will be an ideal catalyst for oxidative dehydrogenation (ODH). The following experiment results indeed evidence that the Co,N-WS2 catalyst displays a high activity in the ODH of 1,2,3,4-tetrahydroquinoline (4H-quinoline) and its derivatives. Therefore, this work provides a good example for the rational design and accurate preparation of functional catalysts, which enables it possible to develop other efficient catalysts with multiple functions. [ABSTRACT FROM AUTHOR]

Heterojunctions modulated internal electric field (IEF) usually result in suboptimal efficiencies in carrier separation and utilization because of the narrow IEF distribution and long migration paths of photocarriers. In this work, we report distinctive bismuth oxyhydroxide compound nanorods (denoted as BOH NRs) featuring surface-exposed open channels and a simple chemical composition; by simply modifying the bulk anion layers to overcome the limitations of heterojunctions, the bulk IEF could be readily modulated. Benefiting from the unique crystal structure and the localization of valence electrons, the bulk IEF intensity increases with the atomic number of introduced halide anions. Therefore, A low exchange ratio (~10%) with halide anions (I–, Br–, Cl–) gives rise to a prominent elevation in carrier separation efficiency and better photocatalytic performance for benzylamine coupling oxidation. Here, our work offers new insights into the design and optimization of semiconductor photocatalysts. Research on the bulk internal electric field (IEF) regulation is significant for designing high-efficiency photocatalysts. Here, the authors report distinctive bismuth oxyhydroxide nanorods photocatalyst and increase the bulk IEF intensity by halogen ions exchange. [ABSTRACT FROM AUTHOR]

Single-atom site (SA) catalysts on N-doped carbon (CN) materials exhibit prominent performance for their active sites being M-Nx. Due to the commonly random doping behaviors of N species in these CN, it is a tough issue to finely regulate their doping types and clarify their effect on the catalytic property of such catalysts. Herein, we report that the N-doping type in CN can be dominated as pyrrolic-N and pyridinic-N respectively through compounding with different metal oxides. It is found that the proportion of distinct doped N species in CN depends on the acidity and basicity of compounded metal oxide host. Owing to the coordination by pyrrolic-N, the SA Cu catalyst displays an enhanced activity (two-fold) for transfer hydrogenation of quinoline to access the valuable molecule tetrahydroquinoline with a good selectivity (99%) under mild conditions. The higher electron density of SA Cu species induced by the predominate pyrrolic-N coordination benefits the hydrogen transfer process and reduces the energy barrier of the hydrogenation pathway, which accounts for the improved catalytic effeciency. [ABSTRACT FROM AUTHOR]

The sintering of supported metal nanoparticles is a major route to the deactivation of industrial heterogeneous catalysts, which largely increase the cost and decrease the productivity. Here, we discover that supported palladium/gold/platinum nanoparticles distributed at the interface of oxide supports and nitrogen-doped carbon shells would undergo an unexpected nitrogen-doped carbon atomization process against the sintering at high temperatures, during which the nanoparticles can be transformed into more active atomic species. The in situ transmission electron microscopy images reveal the abundant nitrogen defects in carbon shells provide atomic diffusion sites for the mobile atomistic palladium species detached from the palladium nanoparticles. More important, the catalytic activity of sintered and deactivated palladium catalyst can be recovered by this unique N-doped carbon atomization process. Our findings open up a window to preparation of sintering-resistant single atoms catalysts and regeneration of deactivated industrial catalysts. Sintering supported metal nanoparticles is the common route to the deactivation of industrial heterogeneous catalysts. Here, the authors report a carbon atomization process that allows one not only to redisperse metal nanoparticles, but also to recover deactivated catalysts. [ABSTRACT FROM AUTHOR]

For electrocatalytic reduction of CO2 to CO, the stabilization of intermediate COOH* and the desorption of CO* are two key steps. Pd can easily stabilize COOH*, whereas the strong CO* binding to Pd surface results in severe poisoning, thus lowering catalytic activity and stability for CO2 reduction. On Ag surface, CO* desorbs readily, while COOH* requires a relatively high formation energy, leading to a high overpotential. In light of the above issues, we successfully designed the PdAg bimetallic catalyst to circumvent the drawbacks of sole Pd and Ag. The PdAg catalyst with Ag-terminated surface not only shows a much lower overpotential (-0.55 V with CO current density of 1 mA/cm2) than Ag (−0.76 V), but also delivers a CO/H2 ratio 18 times as high as that for Pd at the potential of -0.75 V vs. RHE. The issue of CO poisoning is significantly alleviated on Ag-terminated PdAg surface, with the stability well retained after 4 h electrolysis at -0.75 V vs. RHE. Density functional theory (DFT) calculations reveal that the Ag-terminated PdAg surface features a lowered formation energy for COOH* and weakened adsorption for CO*, which both contribute to the enhanced performance for CO2 reduction. [ABSTRACT FROM AUTHOR]

High-efficiency water electrolysis is the key to sustainable energy. Here we report a highly active and durable RuIrOx (x ≥ 0) nano-netcage catalyst formed during electrochemical testing by in-situ etching to remove amphoteric ZnO from RuIrZnOx hollow nanobox. The dispersing-etching-holing strategy endowed the porous nano-netcage with a high exposure of active sites as well as a three-dimensional accessibility for substrate molecules, thereby drastically boosting the electrochemical surface area (ECSA). The nano-netcage catalyst achieved not only ultralow overpotentials at 10 mA cm−2 for hydrogen evolution reaction (HER; 12 mV, pH = 0; 13 mV, pH = 14), but also high-performance overall water electrolysis over a broad pH range (0 ~ 14), with a potential of mere 1.45 V (pH = 0) or 1.47 V (pH = 14) at 10 mA cm−2. With this universal applicability of our electrocatalyst, a variety of readily available electrolytes (even including waste water and sea water) could potentially be directly used for hydrogen production. Water electrolysis is considered a key reaction for future sustainable fuel generation. Here, authors report a three-dimensional RuIrOx nano-netcage catalyst that shows high activities and efficiencies for pH-universal overall water splitting. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation has been widely employed in organic synthesis, by virtue of the green, mild and simple reaction conditions as well as high selectivity. Introducing oxygen vacancies (OVs) with proper concentrations into the photocatalysts has been proven as an effective strategy to boost the catalytic performances. However, the currently used treatment method under high temperature at reducing atmosphere inevitably introduces a large number of OVs at the interior of the catalyst and serving as the recombination centers of carriers. To address this issue, here we develop a facile solvothermal process to prepare ultrathin BiOBr nanosheets with rich surface OVs. This method effectively decreases the bulk of the material and the ratio of interior OVs, rendering most of the OVs exposed on the surfaces which act as exposed catalytic sites and enhance the separation of carriers, therefore significantly elevates the photocatalytic performances. For the photo-oxidation reaction of secondary amines, under the conditions of visible light, ambient temperature and atmosphere, the BiOBr nanosheets featuring rich surface OVs deliver a doubled conversion compared to those with low OV concentrations, and a high selectivity of 99%, a high stability as the performance shows no reduction after 5 times of circular reaction. [ABSTRACT FROM AUTHOR]

We developed a strategy based on coordination polymer to synthesize singleatom site Fe/N and S-codoped hierarchical porous carbon (Fe1/N,S-PC). The as-obtained Fe1/N,S-PC exhibited superior oxygen reduction reaction (ORR) performance with a half-wave potential (E1/2, 0.904 V vs. RHE) that was better than that of commercial Pt/C (E1/2, 0.86 V vs. RHE), single-atom site Fe/N-doped hierarchical porous carbon (Fe1/N-PC) without S-doped (E1/2, 0.85 V vs. RHE), and many other nonprecious metal catalysts in alkaline medium. Moreover, the Fe1/N,S-PC revealed high methanol tolerance and firm stability. The excellent electrocatalytic activity of Fe1/N,S-PC is attributed to the synergistic effects from the atomically dispersed porphyrin-like Fe-N4 active sites, the heteroatom codoping (N and S), and the hierarchical porous structure in the carbon materials. The calculation based on density functional theory further indicates that the catalytic performance of Fe1/N,S-PC is better than that of Fe1/N-PC owing to the sulfur doping that yielded different rate-determining steps. [ABSTRACT FROM AUTHOR]

Correction to: I Nature Communications i https://doi.org/10.1038/s41467-018-07850-2, published online 21 December 2018. These authors contributed equally: Yuanjun Chen, Shufang Ji, Shu Zhao. [Extracted from the article]

Atomically dispersed metal-N-C structures are efficient active sites for catalyzing benzene oxidation reaction (BOR). However, the roles of N and C atoms are still unclear. We report a polymerization-regulated pyrolysis strategy for synthesizing single-atom Fe-based catalysts, and present a systematic study on the coordination effect of Fe-NxCy catalytic sites in BOR. The special coordination environment of single-atom Fe sites brings a surprising discovery: Fe atoms anchored by four-coordinating N atoms exhibit the highest BOR performance with benzene conversion of 78.4% and phenol selectivity of 100%. Upon replacing coordinated N atoms by one or two C atoms, the BOR activities decrease gradually. Theoretical calculations demonstrate the coordination pattern influences not only the structure and electronic features, but also the catalytic reaction pathway and the formation of key oxidative species. The increase of Fe-N coordination number facilitates the generation and activation of the crucial intermediate O=Fe=O species, thereby enhancing the BOR activity. Atomically dispersed metal-N-C are efficient active site for benzene oxidation but the roles of N and C atoms are still unclear. Here the authors report a highly-active single-atom Fe-based benzene oxidation catalyst and provide deep insights into the structure-activity relationship at atomic level. [ABSTRACT FROM AUTHOR]

Efficient, durable and inexpensive electrocatalysts that accelerate sluggish oxygen reduction reaction kinetics and achieve high-performance are highly desirable. Here we develop a strategy to fabricate a catalyst comprised of single iron atomic sites supported on a nitrogen, phosphorus and sulfur co-doped hollow carbon polyhedron from a metal-organic framework@polymer composite. The polymer-based coating facilitates the construction of a hollow structure via the Kirkendall effect and electronic modulation of an active metal center by long-range interaction with sulfur and phosphorus. Benefiting from structure functionalities and electronic control of a single-atom iron active center, the catalyst shows a remarkable performance with enhanced kinetics and activity for oxygen reduction in both alkaline and acid media. Moreover, the catalyst shows promise for substitution of expensive platinum to drive the cathodic oxygen reduction reaction in zinc-air batteries and hydrogen-air fuel cells. Development of fuel cells and metal-air batteries is hindered by electrocatalyst performance, which can be enhanced with uniform and atomically dispersed active sites. Here the authors report an iron-based electrocatalyst for oxygen reduction in cathodes for a zinc-air battery and a hydrogen-air fuel cell. [ABSTRACT FROM AUTHOR]