Search

In acidic proton exchange membrane water electrolysis (PEMWE), the anode oxygen evolution reaction (OER) catalysts rely heavily on the expensive and scarce iridium‐based materials. Ruthenium dioxide (RuO2) with lower price and higher OER activity, has been explored for the similar task, but has been restricted by the poor stability. Herein, we developed an anion modification strategy to improve the OER performance of RuO2 in acidic media. The designed multicomponent catalyst based on sulfate anchored on RuO2/MoO3 displays a low overpotential of 190 mV at 10 mA cm−2 and stably operates for 500 hours with a very low degradation rate of 20 μV h−1 in acidic electrolyte. When assembled in a PEMWE cell, this catalyst as an anode shows an excellent stability at 500 mA cm−2 for 150 h. Experimental and theoretical results revealed that MoO3 could stabilize sulfate anion on RuO2 surface to suppress its leaching during OER. Such MoO3‐anchored sulfate not only reduces the formation energy of *OOH intermediate on RuO2, but also impedes both the surface Ru and lattice oxygen loss, thereby achieving the high OER activity and exceptional durability. [ABSTRACT FROM AUTHOR]

Maximizing hole‐transfer kinetics—usually a rate‐determining step in semiconductor‐based artificial photosynthesis—is pivotal for simultaneously enabling high‐efficiency solar hydrogen production and hole utilization. However, this remains elusive yet as efforts are largely focused on optimizing the electron‐involved half‐reactions only by empirically employing sacrificial electron donors (SEDs) to consume the wasted holes. Using high‐quality ZnSe quantum wires as models, we show that how hole‐transfer processes in different SEDs affect their photocatalytic performances. We found that larger driving forces of SEDs monotonically enhance hole‐transfer rates and photocatalytic performances by almost three orders of magnitude, a result conforming well with the Auger‐assisted hole‐transfer model in quantum‐confined systems. Intriguingly, further loading Pt cocatalyts can yield either an Auger‐assisted model or a Marcus inverted region for electron transfer, depending on the competing hole‐transfer kinetics in SEDs. [ABSTRACT FROM AUTHOR]

Alkaline fuel cells can permit the adoption of platinum group metal‐free (PGM‐free) catalysts and cheap bipolar plates, thus further lowering the cost. With the exploration of PGM‐free hydrogen oxidation reaction (HOR) catalysts, nickel‐based compounds have been considered as the most promising HOR catalysts in alkali. Here we report an interfacial engineering through the formation of nickel‐vanadium oxide (Ni/V2O3) heterostructures to activate Ni for efficient HOR catalysis in alkali. The strong electron transfer from Ni to V2O3 could modulate the electronic structure of Ni sites. The optimal Ni/V2O3 catalyst exhibits a high intrinsic activity of 0.038 mA cm−2 and outstanding stability. Experimental and theoretical studies reveal that Ni/V2O3 interface as the active sites can enable to optimize the hydrogen and hydroxyl bindings, as well as protect metallic Ni from extensive oxidation, thus achieving the notable activity and durability. [ABSTRACT FROM AUTHOR]

Electrosynthesis of hydrogen peroxide (H2O2) in the acidic environment could largely prevent its decomposition to water, but efficient catalysts that constitute entirely earth‐abundant elements are lacking. Here we report the experimental demonstration of narrowing the interlayer gap of metallic cobalt diselenide (CoSe2), which creates high‐performance catalyst to selectively drive two‐electron oxygen reduction toward H2O2 in an acidic electrolyte. The enhancement of the interlayer coupling between CoSe2 atomic layers offers a favorable surface electronic structure that weakens the critical *OOH adsorption, promoting the energetics for H2O2 production. Consequently, on the strongly coupled CoSe2 catalyst, we achieved Faradaic efficiency of 96.7 %, current density of 50.04 milliamperes per square centimeter, and product rate of 30.60 mg cm−2 h−1. Moreover, this catalyst shows no sign of degradation when operating at −63 milliamperes per square centimeter over 100 hours. [ABSTRACT FROM AUTHOR]

Although the Turing structures, or stationary reaction‐diffusion patterns, have received increasing attention in biology and chemistry, making such unusual patterns on inorganic solids is fundamentally challenging. We report a simple cation exchange approach to produce Turing‐type Ag2Se on CoSe2 nanobelts relied on diffusion‐driven instability. The resultant Turing‐type Ag2Se‐CoSe2 material is highly effective to catalyze the oxygen evolution reaction (OER) in alkaline electrolytes with an 84.5 % anodic energy efficiency. Electrochemical measurements show that the intrinsic OER activity correlates linearly with the length of Ag2Se‐CoSe2 interfaces, determining that such Turing‐type interfaces are more active sites for OER. Combing X‐ray absorption and computational simulations, we ascribe the excellent OER performance to the optimized adsorption energies for critical oxygen‐containing intermediates at the unconventional interfaces. [ABSTRACT FROM AUTHOR]

A considerable challenge in the conversion of carbon dioxide into useful fuels comes from the activation of CO2 to CO2.− or other intermediates, which often requires precious‐metal catalysts, high overpotentials, and/or electrolyte additives (e.g. ionic liquids). We report a microwave heating strategy for synthesizing a transition‐metal chalcogenide nanostructure that efficiently catalyzes CO2 electroreduction to carbon monoxide (CO). We found that the cadmium sulfide (CdS) nanoneedle arrays exhibit an unprecedented current density of 212 mA cm−2 with 95.5±4.0 % CO Faraday efficiency at −1.2 V versus a reversible hydrogen electrode (RHE; without iR correction). Experimental and computational studies show that the high‐curvature CdS nanostructured catalyst has a pronounced proximity effect which gives rise to large electric field enhancement, which can concentrate alkali‐metal cations resulting in the enhanced CO2 electroreduction efficiency. [ABSTRACT FROM AUTHOR]