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Ni phosphides and NiCo alloys are extensively explored for their remarkable efficiency in biomass alcohol oxidations, yet the underlying mechanisms remain inadequately understood. This study thoroughly elucidates the roles of Ni, Co, and P in improving the catalytic performance of Ni‐Co‐P catalysts for the electrochemical conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA), a promising biomass‐derived building block replacing terephthalic acid. Phosphorization of Ni results in the partial formation of Ni2P phase and significantly boosts the formation of the reactive NiOOH phase on the surface, which is the crucial catalytic phase for converting HMF into FDCA. The integration of Co into the heterojunction between Ni2P and NiOOH enhances the oxidation reactivity of 5‐formyl‐2‐furancarboxylic acid (FFCA), a pivotal intermediate influencing FDCA productivity, by selectively stabilizing aldehydes, thereby promoting further oxidation rather than surface desorption. in situ/operando spectroscopic analyses consistently highlight the equal significance of the rapid generation of NiOOH and the robust adsorption of reactant molecules at the surface in achieving high catalytic performance. These insights into elemental contributions set a new standard for designing multi‐component electrocatalysts for efficient biomass alcohol oxidation. [ABSTRACT FROM AUTHOR]

Electrochemical hydrogen peroxide (H 2 O 2 ) production via two-electron oxygen reduction reaction (2e - ORR) has received increasing attention as it enables clean, sustainable, and on-site H 2 O 2 production. Mimicking the active site structure of H 2 O 2 production enzymes, such as nickel superoxide dismutase, is the most intuitive way to design efficient 2e - ORR electrocatalysts. However, Ni-based catalysts have thus far shown relatively low 2e - ORR activity. In this work, we present the design of high-performing, atomically dispersed Ni-based catalysts (Ni ADCs) for H 2 O 2 production through understanding the formation chemistry of the Ni-based active sites. The use of a precoordinated precursor and pyrolysis within a confined nanospace were found to be essential for generating active Ni-N x sites in high density and increasing carbon yields, respectively. A series of model catalysts prepared from coordinating solvents having different vapor pressures gave rise to Ni ADCs with controlled ratios of Ni-N x sites and Ni nanoparticles, which revealed that the Ni-N x sites have greater 2e - ORR activity. Another set of Ni ADCs identified the important role of the degree of distortion from the square planar structure in H 2 O 2 electrosynthesis activity. The optimized catalyst exhibited a record H 2 O 2 electrosynthesis mass activity with excellent H 2 O 2 selectivity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The catalytic activity and product selectivity of the electrochemical CO 2 reduction reaction (eCO 2 RR) depend strongly on the local microenvironment of mass diffusion at the nanostructured catalyst and electrolyte interface. Achieving a molecular-level understanding of the electrocatalytic reaction requires the development of tunable metal-ligand interfacial structures with atomic precision, which is highly challenging. Here, the synthesis and molecular structure of a 25-atom silver nanocluster interfaced with an organic shell comprising 18 thiolate ligands are presented. The locally induced hydrophobicity by bulky alkyl functionality near the surface of the Ag 25 cluster dramatically enhances the eCO 2 RR activity (CO Faradaic efficiency, FE CO : 90.3%) with higher CO partial current density (j CO ) in an H-cell compared to Ag 25 cluster (FE CO : 66.6%) with confined hydrophilicity, which modulates surface interactions with water and CO 2 . Remarkably, the hydrophobic Ag 25 cluster exhibits j CO as high as -240 mA cm -2 with FE CO >90% at -3.4 V cell potential in a gas-fed membrane electrode assembly device. Furthermore, this cluster demonstrates stable eCO 2 RR over 120 h. Operando surface-enhanced infrared absorption spectroscopy and theoretical simulations reveal how the ligands alter the neighboring water structure and *CO intermediates, impacting the intrinsic eCO 2 RR activity, which provides atomistic mechanistic insights into the crucial role of confined hydrophobicity., (© 2023 Wiley‐VCH GmbH.)

Cations in an electrolyte modulate microenvironments near the catalyst surface and affect product distribution from an electrochemical CO 2 reduction reaction, and thus, their interaction with intermediate states has been tried to be probed. Herein, we directly observed the cation effect on *CO intermediates on the Cu(OH) 2 -derived catalyst in real time through operando surface-enhanced Raman spectroscopy at high overpotentials (-1.0 V RHE ). Atop *CO peaks are composed of low-frequency binding *CO (*CO LFB ) and high-frequency binding *CO (*CO HFB ) because of their adsorption sites. These two *CO intermediates are found to have different sensitivities to the cation-induced field, and each *CO is proposed to be suitably stabilized for efficient C-C coupling. The proportions between *CO HFB and *CO LFB are dependent on the type of alkali cations, and the increases in the *CO HFB ratio have a high correlation with selective C 2 H 4 production under K + and Cs + , indicating that *CO HFB is the dominant and fast active species. In addition, as the hydrated cation size decreases, *CO LFB is more sensitively red-shifted than *CO HFB , which promotes C-C coupling and suppresses C 1 products. Through time-resolved operando measurements, dynamic changes between the two *CO species are observed, showing the rapid initial adsorption of *CO HFB and subsequently reaching a steady ratio between *CO LFB and *CO HFB .