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Electrochemical nitrate reduction reaction (NtrRR) has been emerging as an appealing route for both water treatment and NH3 synthesis. Herein, we report the structure analysis and electrocatalytic performance of a novel homoleptic alkynyl-protected Ag20Cu12 nanocluster (Ag20Cu12 in short) with atomic precision, which has eight free electrons and displays characteristic absorbance feature. Single crystal X-ray diffraction (SC-XRD) discloses that, it adopts a Ag14 kernel capped by three Ag2Cu4(C≡CArF)8 metal–ligand binding motifs in the outer shell. Ag20Cu12 exhibited excellent catalytic performance toward NtrRR, as manifested by the superior NH3 Faradaic efficiency (FE, 84.6%) and yield rate (0.138 mmol·h−1·mg−1) than the homoleptic alkynyl-protected Ag32 nanoclusters. Additionally, it demonstrates good catalytic recycling capability. Density functional theory (DFT) calculations revealed that, the de-ligated Ag20Cu12 cluster can expose the available AgCu bimetallic sites as the efficient active sites for NH3 formation. In particular, the participation of Cu sites greatly facilitates the initial capture of NO3− and simultaneously promotes the selectivity of the final product. This study discovers a novel homoleptic alkynyl-protected AgCu superatom, and offers a great example to elucidate the structure–performance relationship of bimetallic catalyst for NtrRR and other multiple protons/electrons coupled electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

We report the synthesis, structure, and electrochemical hydrogen evolution reaction (HER) performance of two alkynyl and halogen coprotected AuAg alloy nanoclusters, namely Au24Ag20(tBuPh-C≡C)24Cl2 (NC 1 for short) and Au22Ag22(tBuC≡C)16Br3.28Cl2.72 (NC 2 for short). Single crystal X-ray structural analysis revealed that the two nanoclusters possess a rather similar core@shell@shell keplerate metal core configuration to M12@M20@M12 with the main difference in the outermost shell (Au12vs. Au10Ag2). Interestingly, such a subtle difference in the two-metal-atoms results in different optical absorbance features and drastically different HER performances. Both NCs have excellent long-term stability for the HER, but NC 1 possesses superior activity to NC 2, and density functional theory calculations disclosed that the binding energy of hydrogen to form the key *H intermediate for NC 1 is much lower and hence it adopts a more energetically feasible HER pathway. [ABSTRACT FROM AUTHOR]

We report the fabrication of homoleptic alkynyl‐protected Ag15(C≡C‐tBu)12+ (abbreviated as Ag15) nanocluster and its electrocatalytic properties toward CO2 reduction reaction. Crystal structure analysis reveals that Ag15 possesses a body‐centered‐cubic (BCC) structure with an Ag@Ag8@Ag6 metal core configuration. Interestingly, we found that Ag15 can adsorb CO2 in the air and spontaneously self‐assembled into one‐dimensional linear material during the crystal growth process. Furthermore, Ag15 can convert CO2 into CO with a faradaic efficiency of ca. 95.0 % at −0.6 V and a maximal turnover frequency of 6.37 s−1 at −1.1 V along with excellent long‐term stability. Finally, density functional theory (DFT) calculations disclosed that Ag15(C≡C‐tBu)11+ with one alkynyl ligand stripping off from the intact cluster can expose the uncoordinated Ag atom as the catalytically active site for CO formation. [ABSTRACT FROM AUTHOR]

To advance the development of atomically precise Ag and Ag-alloyed nanoclusters, it is critical to develop effective synthetic methods. Herein, we successfully extend the CTAB (cetyl trimethyl ammonium bromide) reverse micelle method to synthesize a high-purity Ag44(p-MBA)30 (p-MBA = para-mercaptobenzoic acid) nanocluster and its corresponding alloy cluster Au12Ag32(p-MBA)30 in a short time (15 min and 5 min), with a high yield of ∼83% and ∼85%, respectively. Furthermore, the mechanism regarding the reverse micelle method has been clearly elucidated. Through characterizing the reaction system by Raman spectroscopy and NMR spectroscopy techniques, it can be revealed that employing CTAB to form reverse micelles to construct a sealed chemical environment is critical for realizing the fast and high-yield synthesis. [ABSTRACT FROM AUTHOR]

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)24 formation process, Au22(PA)18 as key intermediate was identified. Meanwhile, Au22(PA)18 can be synthesized under a low amount of reductant, and by employing more reductants, Au22(PA)18 can turn into Au36(PA)24 eventually. Moreover, the structure evolution from Au22(PA)18 to Au36(PA)24 is proposed, where four Au13 cuboctahedra can yield one Au28 kernel. 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. [ABSTRACT FROM AUTHOR]

Aqueous Zn batteries exhibit significant research potential owing to their environmental friendliness and high energy density. Nevertheless, the formation of dendrites on the zinc anode and the sluggish diffusion kinetics of zinc ions adversely affect the cycle life of zinc ion batteries. In this study, we employ porous V 2 CT x (MVMX) as a protective layer for the zinc anode. The uniform porous structure of MVMX promotes active site exposure and facilitates the transport of zinc ions. Remarkably, the Zn@Ti half-cell demonstrated an average CE of 99.7% in 1500 cycles. Furthermore, the Zn-Zn symmetric battery exhibited stable cycling for 1600 h at current densities of 5 mA cm -2 and 1 mAh cm -2 . Additionally, the MVMX@Zn||V 2 O 5 full cell exhibited a capacity of 198 mAh g -1 and retained a capacity of 124.75 mAh g -1 after 5000 cycles at 1 A g -1 , demonstrating the potential of employing alternative MXenes for fabricating stable zinc anodes.

We report the synthesis, structure analysis, and electrocatalytic CO 2 reduction application of Ag 19 Cu 2 (CCAr F ) 12 (PPh 3 ) 6 Cl 6 (abbreviated as Ag 19 Cu 2 , CCAr F : 3,5-bis(trifluoromethyl)phenylacetylene) nanoclusters. Ag 19 Cu 2 has characteristic absorbance features and is a superatomic cluster with 2 free valence electrons. Single-crystal X-ray diffraction (SC-XRD) revealed that the metal core of Ag 19 Cu 2 is composed of an Ag 11 Cu 2 icosahedron connected by two Ag 4 tetrahedra at the two terminals of the Cu-Ag-Cu axis. Notably, Ag 19 Cu 2 exhibited excellent catalytic performance in the electrochemical CO 2 reduction reaction (eCO 2 RR), manifested by a high CO faradaic efficiency of 95.26% and a large CO current density of 257.2 mA cm -2 at -1.3 V. In addition. Ag 19 Cu 2 showed robust long-term stability, with no significant drop in current density and FE CO after 14 h of continuous operation. Density functional theory (DFT) calculations disclosed that the high selectivity of Ag 19 Cu 2 for CO in the eCO 2 RR process is due to the shedding of the -CCAr F ligand from the Ag atom at the very center of the Ag 4 unit, exposing the active site. This study enriches the potpourri of alkynyl-protected bimetallic nanoclusters and also highlights the great advantages of using atomically precise metal nanoclusters to probe the atomic-level structure-performance relationship in the catalytic field.

Electrochemically converting NO 3 - compounds into ammonia represents a sustainable route to remove industrial pollutants in wastewater and produce valuable chemicals. Bimetallic nanomaterials usually exhibit better catalytic performance than the monometallic counterparts, yet unveiling the reaction mechanism is extremely challenging. Herein, we report an atomically precise [Ag 30 Pd 4 (C 6 H 9 ) 26 ](BPh 4 ) 2 (Ag 30 Pd 4 ) nanocluster as a model catalyst toward the electrochemical NO 3 - reduction reaction (eNO 3 - RR) to elucidate the different role of the Ag and Pd site and unveil the comprehensive catalytic mechanism. Ag 30 Pd 4 is the homoleptic alkynyl-protected superatom with 2 free electrons, and it has a Ag 30 Pd 4 metal core where 4 Pd atoms are located at the subcenter of the metal core. Furthermore, Ag 30 Pd 4 exhibits excellent performance toward eNO 3 - RR and robust stability for prolonged operation, and it can achieve the highest Faradaic efficiency of NH 3 over 90%. In situ Fourier-transform infrared study revealed that a Ag site plays a more critical role in converting NO 3 - into NO 2 - , while the Pd site makes a major contribution to catalyze NO 2 - into NH 3 . The bimetallic nanocluster adopts a tandem catalytic mechanism rather than a synergistic catalytic effect in eNO 3 - RR. Such finding was further confirmed by density functional theory calculations, as they disclosed that Ag is the most preferable binding site for NO 3 - , which then binds a water molecule to release NO 2 - . Subsequently, NO 2 - can transfer to the vicinal exposed Pd site to promote NH 3 formation.

We report the first homoleptic alkynyl-protected AgCu superatomic nanocluster [Ag 9 Cu 6 ( t BuC[triple bond, length as m-dash]C) 12 ] + (NC 1 , also Ag 9 Cu 6 in short), which has a body-centered-cubic structure with a Ag 1 @Ag 8 @Cu 6 metal core. Such a configuration is reminiscent of the reported AuAg bimetallic nanocluster [Au 1 @Ag 8 @Au 6 ( t BuC[triple bond, length as m-dash]C) 12 ] + (NC 2 , also Au 7 Ag 8 in short), which is also synthesized by an anti-galvanic reaction (AGR) approach with a very high yield for the first time in this study. Despite a similar Ag 8 cube for both NCs, structural anatomy reveals that there are some subtle differences between NCs 1 and 2 . Such differences, plus the different M 1 kernel and M 6 octahedron, lead to significantly different optical absorbance features for NCs 1 and 2 . Density functional theory calculations revealed the LUMO and HOMO energy levels of NCs 1 and 2 , where the characteristic absorbance peaks can be correlated with the discrete molecular orbital transitions. Finally, the stability of NCs 1 and 2 at different temperatures, in the presence of an oxidant or Lewis base, was investigated. This study not only enriches the M 15 + series, but also sets an example for correlating the structure-property relationship in alkynyl-protected bimetallic superatomic clusters., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)