Toward Efficient Carbon and Water Cycles: Emerging Opportunities with Single‐Site Catalysts Made of 3d Transition Metals

Abstract

Advances in the chemical and electrochemical transformation of carbon and water are vital for delivering affordable and environmentally friendly energy sources and chemicals. Central to this challenge is the performance of materials. Traditionally, noble metal particles or metal-complexes have been used as catalysts for many reactions. Recently, 3d transition-metal single-site catalysts (3dTM-SSCs) have emerged as potentially transformational candidates for the next generation highperformance noble-metal-free catalysts. Designing catalysts at the molecular level can lead to a more efficient utilization of metal atoms and at the same time enhance catalytic performance under harsh reaction conditions. Despite these promises, several fundamental issues remain, in particular the structural evolution of 3dTM-SSCs during the synthesis, the molecular-level insights into the structure of the active sites, catalytic mechanisms, and the long-term cycling stability. In this progress report, the material chemistries that facilitate the 3dTM-SSCs generation through the controlled synthesis are discussed, and the underlying performance descriptors that can tune the catalytic properties in various critical reactions in carbon and water cycles are elucidated. The current challenges and possible solutions for improving these novel catalytic materials are also highlighted. Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff)) Published online: ((will be filled in by the editorial staff))

Atomic Co decorated free-standing graphene electrode assembly for efficient hydrogen peroxide production in acid

“…40 This might be ascribed to the difference in the metal–nitrogen coordination geometry, where Co is coordinated with pyridinic N ( T d symmetry) in CoN 4 /VG rather than pyrrolic N ( D 4h symmetry) in CoPc molecules. 41 More detailed information of the atomic Co species in CoN 4 /VG was further investigated by analysing the Fourier transformed (FT) Co K-edge EXAFS spectra. As shown in Fig.…”

Microenvironment modulation of single-atom catalysts and their roles in electrochemical energy conversion

“…SACs have shown excellent activity and selectivity in CO 2 RR for the conversion of CO 2 into value-added chemicals such as CO, formic acid, C 2 products, etc. (31,(139)(140)(141)(142)(143). Microenvironment engineering of SACs offers great opportunities for reducing the overpotential of CO 2 RR and improving the selectivity for the desired products.…”

Recent Progress in Single‐Atom Catalysts for Photocatalytic Water Splitting

“…[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] Due to the maximized atom utilization efficiency (Scheme 1), SACs have exhibited great potential in photocatalytic water splitting, which can provide effective sites for proton reduction. [49][50][51] With the aid of SACs, watermolecule adsorption and charge transfer can be facilitated under light irradiation, resulting in rapid conversion from solar to hydrogen energy. [50,52] Based on the reaction mechanism, SACs can influence the key three steps involved in the process of photocatalytic water splitting, due to the interaction between single metal atoms and supports.…”