Pt Single Atoms Supported on Defect Ceria as an Active and Stable Dual-Site Catalyst for Alkaline Hydrogen Evolution.

This work evaluates the feasibility of alkaline hydrogen evolution reaction (HER) using Pt single-atoms (1.0 wt %) on defect-rich ceria (Pt1/CeOx) as an active and stable dual-site catalyst. The catalyst displayed a low overpotential and a small Tafel slope in an alkaline medium. Moreover, Pt1/CeOx presented a high mass activity and excellent durability, competing with those of the commercial Pt/C (20 wt %). In this picture, the defective CeOx is active for water adsorption and dissociation to create H* intermediates, providing the first site where the reaction occurs. The H* intermediate species then migrate to adsorb and react on the Pt2+ isolated atoms, the site where H2 is formed and released. DFT calculations were also performed to obtain mechanistic insight on the Pt1/CeOx catalyst for the HER. The results indicate a new possibility to improve the state-of-the-art alkaline HER catalysts via a combined effect of the O vacancies on the ceria support and Pt2+ single atoms.

Data on a high electrocatalytic activity of metal-WO3 nanocomposite electrocatalysts for hydrogen evolution reaction.

The data given in this article are related to the research article entitled "High electrocatalytic activity of Rh-WO3 electrocatalyst for hydrogen evolution reaction under the acidic, alkaline, and alkaline seawater electrolytes (N.-A. Nguyen et al., 2023) [1]. In this work, metal-WO3 nanocomposites were synthesized and used as electrocatalysts for hydrogen evolution reaction (HER) performance. The morphology and chemical properties of the prepared metal-WO3 nanocomposites were investigated by using scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) techniques.

Modulating Water Splitting Kinetics via Charge Transfer and Interfacial Hydrogen Spillover Effect for Robust Hydrogen Evolution Catalysis in Alkaline Media.

Designing and synthesizing advanced electrocatalysts with superior intrinsic activity toward hydrogen evolution reaction (HER) in alkaline media is critical for the hydrogen economy. Herein, a novel Ir@Rhene heterojunction electrocatalyst is synthesized via epitaxially confining ultrasmall and low-coordinate Ir nanoclusters on the ultrathin Rh metallene accompanying the formation of Ir/IrO2 Janus nanoparticles. The as-prepared heterojunctions display outstanding alkaline HER activity, with an overpotential of only 17 mV at 10 mA cm-2 and an ultralow Tafel slope of 14.7 mV dec-1 . Both structural characterizations and theoretical calculations demonstrate that the Ir@Rhene heterointerfaces induce charge density redistribution, resulting in the increment of the electron density around the O atoms in the IrO2 site and thus delivering much lower water dissociation energy. In addition, the dual-site synergetic effects between IrO2 and Ir/Rh interface trigger and improve the interfacial hydrogen spillover, thereby subtly avoiding the steric blocking of the active site and eventually accelerating the alkaline HER kinetics.

WO3 -Assisted Synergetic Effect Catalyzes Efficient and CO-Tolerant Hydrogen Oxidation for PEMFCs.

Developing anode catalysts with substantially enhanced activity for hydrogen oxidation reaction (HOR) and CO tolerance performance is of great importance for the commercial applications of proton exchange membrane fuel cells (PEMFCs). Herein, an excellent CO-tolerant catalyst (Pd-WO3 /C) has been fabricated by loading Pd nanoparticles on WO3 via an immersion-reduction route. A remarkably high power density of 1.33 W cm-2 at 80 °C is obtained by using the optimized 3Pd-WO3 /C as the anode catalyst of PEMFCs, and the moderately reduced power density (73% remained) in CO/H2 mixed gas can quickly recover after removal of CO-contamination from hydrogen fuel, which is not possible by using Pt/C or Pd/C as anode catalyst. The prominent HOR activity of 3Pd-WO3 /C is attributed to the optimized interfacial electron interaction, in which the activated H* adsorbed on Pd species can be effectively transferred to WO3 species through hydrogen spillover effect and then oxidized through the H species insert/output effect during the formation of Hx WO3 in acid electrolyte. More importantly, a novel synergetic catalytic mechanism about excellent CO tolerance is proposed, in which Pd and WO3 respectively absorbs/activates CO and H2 O, thus achieving the CO electrooxidation and re-exposure of Pd active sites for CO-tolerant HOR.

Patchwork-Structured Heterointerface of 1T-WS2/a-WO3 with Sustained Hydrogen Spillover as a Highly Efficient Hydrogen Evolution Reaction Electrocatalyst.

Using tungsten disulfide (WS2) as a hydrogen evolution reaction (HER) electrocatalyst brought on several ways to surpass its intrinsic catalytic activity. This study introduces a nanodomain tungsten oxide (WO3) interface to 1T-WS2, opening a new route for facilitating the transfer of a proton to active sites, thereby enhancing the HER performance. After H2S plasma sulfurization on the W layer to realize nanocrystalline 1T-WS2, subsequent O2 plasma treatment led to the formation of amorphous WO3 (a-WO3), resulting in a patchwork-structured heterointerface of 1T-WS2/a-WO3 (WSO). Addition of a hydrophilic interface (WO3) facilitates the hydrogen spillover effect, which represents the transfer of absorbed protons from a-WO3 to 1T-WS2. Moreover, the faster response of the cathodic current peak (proton insertion) in cyclic voltammetry is confirmed by the higher degree of oxidation. The rationale behind the faster proton insertion is that the introduced a-WO3 works as a proton channel. As a result, WSO-1.2 (the ratio of 1T-WS2 to a-WO3) exhibits a remarkable HER activity in that 1T-WS2 consumes more protons provided by the channel, showing an overpotential of 212 mV at 10 mA/cm2. Density functional theory calculations also show that the WO3 phase gives higher binding energies for initial proton adsorption, while the 1T-WS2 phase shows reduced HER overpotential. This improved catalytic performance demonstrates a novel strategy for water splitting to actively elicit the related reaction via efficient proton transport.

Reversed Charge Transfer and Enhanced Hydrogen Spillover in Platinum Nanoclusters Anchored on Titanium Oxide with Rich Oxygen Vacancies Boost Hydrogen Evolution Reaction.

The catalytic activity of metal clusters is closely related with the support; however, knowledge on the influence of the support on the catalytic activity is scarce. We demonstrate that Pt nanoclusters (NCs) anchored on porous TiO2 nanosheets with rich oxygen vacancies (VO -rich Pt/TiO2 ) and deficient oxygen vacancies (VO -deficient Pt/TiO2 ), display significantly different catalytic activity for the hydrogen evolution reaction (HER), in which VO -rich Pt/TiO2 shows a mass activity of 45.28 A mgPt -1 at -0.1 V vs. RHE, which is 16.7 and 58.8 times higher than those of VO -deficient Pt/TiO2 and commercial Pt/C, respectively. DFT calculations and in situ Raman spectra suggest that porous TiO2 with rich oxygen vacancies can simultaneously achieve reversed charge transfer (electrons transfer from TiO2 to Pt NCs) and enhanced hydrogen spillover from Pt NCs to the TiO2 support, which leads to electron-rich Pt NCs being amenable to proton reduction of absorbed H*, as well as the acceleration of hydrogen desorption at Pt catalytic sites-both promoting the HER. Our work provides a new strategy for rational design of highly efficient HER catalysts.

Pt nanocatalysts supported on reduced graphene oxide for selective conversion of cellulose or cellobiose to sorbitol.

Pt nanocatalysts loaded on reduced graphene oxide (Pt/RGO) were prepared by means of a convenient microwave-assisted reduction approach with ethylene glycol as reductant. The conversion of cellulose or cellobiose into sorbitol was used as an application reaction to investigate their catalytic performance. Various metal nanocatalysts loaded on RGO were compared and RGO-supported Pt exhibited the highest catalytic activity with 91.5 % of sorbitol yield from cellobiose. The catalytic performances of Pt nanocatalysts supported on different carbon materials or on silica support were also compared. The results showed that RGO was the best catalyst support, and the yield of sorbitol was as high as 91.5 % from cellobiose and 58.9 % from cellulose, respectively. The improvement of catalytic activity was attributed to the appropriate Pt particle size and hydrogen spillover effect of Pt/RGO catalyst. Interestingly, the size and dispersion of supported Pt particles could be easily regulated by convenient adjustment of the microwave heating temperature. The catalytic performance was found to initially increase and then decrease with increasing particle size. The optimum Pt particle size was 3.6 nm. These findings may offer useful guidelines for designing novel catalysts with beneficial catalytic performance for biomass conversion.