Atomically precise metal nanoclusters for(photo)electroreduction of CO_(2): Recent advances, challenges and opportunities

To alleviate the global warming by removing excess CO_(2) and converting them into value-added chemicals,(photo)electrochemical reduction has been recognized as a promising strategy.As the CO_(2) reduction reaction(CO_(2) RR) is involved with multiple electrons and multiple products,plus the complexity of the surface chemical environment of the catalyst,it is extremely challenging to establish the structure/function relationship.Atomically precise metal nanoclusters(NCs),with crystallographically resolved structure,molecule-like characters and strong quantum confinement effects,have been emerging as a new type of catalyst for CO_(2) RR,and more importantly,they can provide an ideal platform to unravel the comprehensive mechanistic insights and establish the structure/function relationship eventually.In this review,the recent advances regarding employing molecular metal NCs with well-defined structure including Au NCs,Au-based alloy NCs,Ag NCs,Cu NCs for CO_(2) RR and relevant mechanistic studies are discussed,and the opportunities and challenges are proposed at the end for paving the development of CO_(2) RR by using atomically precise metal NCs.

A synchronous nucleation and passivation strategy for controllable synthesis of Au36(PA)24: unveiling the formation process and the role of Au22(PA)18 intermediate

Despite the recent progress on controllable synthesis of alkynyl-protected Au nanoclusters,the effective synthetic means are very limited and the cluster formation process still remains puzzling.Here,we develop a novel synchronous nucleation and passivation strategy to fabricate Au36(PA)24(PA=phenylacetylenyl) nanoclusters with high yield.In Au36(PA)24formation process,Au22(PA)18as key intermediate was identified.Meanwhile,Au22(PA)18can be synthesized under a low amount of reductant,and by employing more reductants,Au22(PA)18can turn into Au36(PA)24eventually.Moreover,the structure evolution from Au22(PA)18to Au36(PA)24is proposed,where four Au13cuboctahedra can yield one Au28kernel.Finally,the ratiocination is verified by the good accordance between the predicted intermediate/product ratio and the experimental value.This study not only offers a novel synthetic strategy,but also sheds light on understanding the structural evolution process of alkynyl-protected Au nanoclusters at atomic level.

Homoleptic alkynyl-protected Ag_(32 )nanocluster with atomic precision: Probing the ligand effect toward CO_(2) electroreduction and 4-nitrophenol reduction

We report a superatomic homoleptic alkynyl-protected Ag_(32)L_(24)(L=3,5-bis(trifluoromethylbenzene)acetylide,Ag_(32) for short)nanocluster with atomic precision,which possesses eight free electrons.Ag_(32) is formed by an Ag17 core with C3 symmetry and the remaining 15 Ag atoms bond to each other and coordinate with the 24 surface ligands.When applied as electrocatalyst for CO_(2) reduction reaction(CO_(2)RR),Ag_(32) exhibited the highest Faradaic efficiency(FE)of CO up to 96.44%at−0.8 V with hydrogen evolution being significantly suppressed in a wide potential range,meanwhile it has a reaction rate constant of 0.242 min−1 at room temperature and an activation energy of 45.21 kJ·mol−1 in catalyzing the reduction of 4-nitrophenol,both markedly superior than the thiolate and phosphine ligand co-protected Ag_(32) nanocluster.Such strong ligand effect was further understood by density functional theory(DFT)calculations,as it revealed that,one single ligand stripping off from the intact cluster can create the undercoordinated Ag atom as the catalytically active site for both clusters,but alkynyl-protected Ag_(32) nanocluster possesses a smaller energy barrier for forming the key*COOH intermediate in CO_(2)RR,and favors the adsorption of 4-nitrophenol.This study not only discovers a new member of homoleptic alkynyl-protected Ag nanocluster,but also highlights the great potentials of employing alkynyl-protected Ag nanoclusters as bifunctional catalysts toward various reactions.