Nurturing the marriages of single atoms with atomic clusters and nanoparticles for better heterogeneous electrocatalysis

Abstract

Single‐atom catalysts, featuring some of the most unique activities, selectivity, and high metal utilization, have been extensively studied over the past decade. Given their high activity, selectivity, especially towards small molecules or key intermediate conversions, they can be synergized together with other active species (typically other single atoms, atomic clusters, or nanoparticles) in either tandem or parallel or both, leading to much better performance in complex catalytic processes. Although there have been reports on effectively combining the multiple components into one single catalytic entity, the combination and synergy between single atoms and other active species have not been reviewed and examined in a systematic manner. Herein, in this overview, the key synergistic interactions, binary complementary effects, and the bifunctional functions of single atoms with other active species are defined and discussed in detail. The integration functions of their marriages are investigated with particular emphasis on the homogeneous and heterogeneous combinations, spatial distribution, synthetic strategies, and the thus‐derived outstanding catalytic performance, together with new light shined on the catalytic mechanisms by zooming in several case studies. The dynamic nature of each of the active species and in particular their interactions in such new catalytic entities in the heterogeneous electrocatalytic processes are visited, on the basis of the in situ/operando evidence. Last, we feature the current challenges and future perspectives of these integrated catalytic entities that can offer guidance for advanced catalyst design by the rational combination and synergy of binary or multiple active species.

Disordered spinel cobalt oxide electrocatalyst for highly enhanced HER activity in an alkaline medium

“…[6][7][8] Different strategies including engineering metal-metal oxide composition, creating defects and direct fabrication on conducting substrates have been studied in recent years to find electrocatalysts with enhanced activity. [9][10][11][12] Furthermore, most of the reported catalysts showed strong HER activity in acidic medium; however, neutral or alkaline medium efficient HER electrocatalysts are more preferable from a practical point of view due to the corrosive nature of acidic media. 13 However, the additional step, water dissociation, involved in the HER mechanism in an alkaline or neutral medium requires a higher overpotential with transition metal catalysts and also with platinum-group metal catalysts.…”

Improved hydrogen evolution performance by engineering bimetallic AuPd loaded on amino and nitrogen functionalized mesoporous hollow carbon spheres

“…Fourthly, the more electron depletion state of Pd in Au 0.3 Pd 0.7 /NH 2 -N-HMCS caused by metal-support interactions and electron synergetic effect can accelerate the C-H cleavage in the adsorbed formate and the formation of H À . [43][44][45]…”

Electrochemically Tuned Synergistic Nano‐Interface of a Tertiary Ni(OH)2−NiO(OH)/NixP Heterojunction Material for Enhanced and Durable Alkaline Water Splitting

“…A mechanistically faster oxygen evolution (OER) promotes a progressive hydrogen evolution (HER) as well, as both occur simultaneously in an electrolytic cell. Hence it can be said that any attempt to enhance the rate of oxygen evolution from the catalytic surface would eventually contribute to a quicker hydrogen production [4–6] . In short, it is a must to develop effective bifunctional electro‐catalysts for overall water splitting to kick‐start the hydrogen economy.…”

“…Hence it can be said that any attempt to enhance the rate of oxygen evolution from the catalytic surface would eventually contribute to a quicker hydrogen production. [4][5][6] In short, it is a must to develop effective bifunctional electro-catalysts for overall water splitting to kick-start the hydrogen economy. Ruthenium on carbon (Ru/C) has been the benchmark catalyst for OER and platinum on carbon (Pt/C) for HER.…”