Shunhan Jia

The dynamic structural reconstruction of Cu-based catalysts profoundly influences activity, selectivity and stability during electrochemical CO₂ reduction (CO₂RR). However, it lacks standardized methodologies for probing and actively managing these transformations. Here we present a modular, reproducible Protocol that integrates electrochemical control, in situ/operando spectroscopy and mechanistic analysis to systematically investigate and regulate Cu catalyst reconstruction under CO₂RR conditions. This Protocol establishes a comprehensive ‘reconstruction–understanding–intervention’ workflow comprising (1) the identification and taxonomy of reconstruction phenomena, (2) quantification of electrochemical and environmental factors governing reconstruction, (3) correlation of structural dynamics with catalytic behavior through complementary in situ/operando Raman, infrared, X-ray absorption spectroscopy and quasi-in situ X-ray photoelectron spectroscopy measurements, and (4) development of rational reconstruction-control strategies that steer catalysts toward desired active states. A systematic approach is delineated to correlate reconstruction dynamics with catalytic performance and actively direct the process toward desired active states via three primary strategies: catalyst structure modulation, electrochemical operation regulation and reaction microenvironment management. The methodology is validated using representative Cu-based systems, including commercial Cu, oxide-derived Cu and bimetallic Cu–X catalysts, demonstrating enhanced performance and stability of CO₂RR. This workflow also provides an adaptable framework for investigating dynamic surface evolution in other electrocatalytic reactions. This Protocol provides useful framework for the rational development of adaptive, stable and selective electrocatalysts.

Multi-step cascade reactions that couple electrochemical and non-electrochemical steps are an appealing strategy for designing efficient reactions. However, their development is fundamentally constrained by mechanistic uncertainty, leading to uncontrolled side reactions. Herein, a spatially separated active-site strategy is developed, using the electrosynthesis of cyclohexanone oxime (CHO) as a model, to bias the reaction toward the interface confinement pathway via a designed Zn-based mixed-site catalyst. Based on controlled experiments, in situ characterization and theoretical calculations, we demonstrate that the Zn single-atom and Zn nanoparticle site can adsorb N-containing intermediates and cyclohexanone (CYC), respectively. It is demonstrated that 99.5% cyclohexanone conversion, 50.3% cyclohexanone oxime Faradaic efficiency, 100% carbon selectivity, and 41.0% nitrogen selectivity can be achieved, while maintaining performance stability over 200 h. Detailed mechanistic analysis indicates that at suitable Zn single-atom and nanoparticle ratio, interfacial hydrogen-bond network of water is optimized, which can modulate both adsorption orientation and coverage of *CYC and the coverage of N-containing intermediates to enhance the desired reaction pathway.

Three interaction models are introduced to help analyse intermediate behaviour and reaction pathways at key reaction steps.

Hydroxylamine (NH₂OH) has a broad range of applications. Electrocatalytic semireduction of nitrate (NO₃^-) to NH₂OH is a promising pathway for its sustainable production. However, the reported route typically led to either insufficient or excessive hydrogenation because the mismatch between supply and demand of active species during electrocatalysis remains a critical challenge, resulting in poor selectivity to NH₂OH. Herein, we demonstrate an interfacial water (H₂O) frustration strategy to achieve highly selective electrocatalytic semireduction of nitrate (NO₃^-) to hydroxylamine (NH₂OH). By engineering the electric double layer (EDL) through alkali metal cation modulation, we precisely regulated the activation of interfacial H₂O to inhibit excessive active hydrogen (*H) generation, thereby controlling the *H supply. In addition, tensile-strained bibased catalysts promoted *NO intermediate formation, enhancing *H demand and suppressing over-reduction to NH₃. It achieved a Faradaic efficiency (FE) of 93.9% for NH₂OH at 120 mA cm^-2 under acidic conditions, which enabled the gram-scale synthesis of industrially relevant oximes with high nitrogen selectivity. Remarkably, this work achieved the highest NH₂OH FE under industrial-level current densities (>100 mA cm^-2). This work provided a generalizable approach for steering semireduction pathways through interfacial H₂O frustration, which constructs the supply-demand balance of essential active species involved in electrocatalytic reactions.

The electroreduction of nitrate (NO₃^-) offers a promising pathway for carbon-free NH₃ production and nitrogen cycle management. Pulsed NO₃^- electroreduction has demonstrated to enable the improvement of catalytic performance, but the underlying mechanisms remain little understood. Herein, we tune the Cu catalyst structure and steer the key N-containing intermediate adsorption configuration during pulsed NO₃^- electroreduction. By applying different positive and negative potentials, in situ dynamic restructuring of the Cu catalyst and the regulation of local microenvironment have been revealed. According to detailed in situ characterizations and theoretical calculations, periodic Cu oxidation occurs within specific potential ranges from -0.2 V to 0.2 V vs. saturated Ag/AgCl, facilitating the transition of *NO adsorption configuration and thereby enhancing NH₃ formation. It can also increase NO₂^- coverage on Cu surface and inhibit side reactions. Conversely, the enhanced catalytic preformation in potential ranges from -1.2 V to -0.2 V was only attributed to the intrinsic characteristics of pulsed electrolysis. This study not only reveals the in-depth understanding of pulsed NO₃^- electrolysis, but also offers a general way of optimizing other electrocatalytic reactions.

Using CO₂ as the carbon source for electrocatalytic C-N coupling with organic amino compounds to achieve N-methylation reactions offers an appealing route for synthesizing valuable N-containing chemicals, mitigating CO₂ emissions, and storing renewable energy but is challenging. Herein, we report the first work to design heterostructured Cu-Ni-Al electrocatalysts for N-methylation. Using 4-hydroxypiperidine (PD) as a substrate, high electrocatalytic performance with a 1-methyl-4-piperidinol (MPD) faradaic efficiency (FE) of 29.3%, a N-methylation selectivity of 100%, a C-selectivity of 78.3%, and a formation rate of 15.4 mmol g^-1 h^-1 was achieved in the H-cell. It also showed remarkable recycling stability. Control experiments and in situ measurements confirmed the key role of the CuO/NiAl₂O₄ heterostructure for the N-methylation reaction. Moreover, a combination of experimental and density functional theory (DFT) calculations demonstrated that CO₂ converted to the *H₂CO intermediate on the CuO/NiAl₂O₄ heterostructure, which underwent chemical condensation and subsequent reduction with nucleophilic amino compounds on the CuO/NiAl₂O₄ heterostructure, leading to high efficiency toward N-methylation. Further investigation showed that this system could also be extended to other amino compounds.

Adiponitrile (ADN) has wide applications, especially in the polymer industry. With the substantial and increasing global demand for ADN, effective production of ADN using safe and abundant starting materials is highly desirable but very challenging. Herein, we discovered that CuBr, combined with 1,10-phenanthroline (phen), could effectively promote the ammoxidation reaction of cyclohexanone to ADN with a yield of >99% using aqueous ammonia as the nitrogen source and O₂ as the terminal oxidant under mild reaction conditions (80 °C, 5 atm O₂). Moreover, cyclic ketones with various carbon numbers and substituent groups could also be converted into the corresponding dinitrile products with high yields. A detailed mechanistic study revealed that the reaction proceeded through a radical-mediated pathway, and the reason for the high selectivity to ADN was discussed. This study offers a new, simple, and cost-effective route to produce ADN and other dinitrile products.

The electrocatalytic reaction pathway is highly dependent on the intrinsic structure of the catalyst. CO₂/CO electroreduction has recently emerged as a potential approach for obtaining C₂₊ products, but it is challenging to achieve high selectivity for a single C₂₊ product. Herein, we develop a Cu atomic ensemble that satisfies the appropriate site distance and coordination environment required for electrocatalytic CO-to-acetate conversion, which shows outstanding overall performance with an acetate Faradaic efficiency of 70.2% with a partial current density of 225 mA cm^-2 and a formation rate of 2.1 mmol h^-1 cm^-2. Moreover, a single-pass CO conversion rate of 91% and remarkable stability can be also obtained. Detailed experimental and theoretical investigations confirm the significant advantages of the Cu atomic ensembles in optimizing C-C coupling, stabilizing key ketene intermediate (*CCO), and inhibiting the *HOCCOH intermediate, which can switch the CO reduction pathway from the ethanol/ethylene on the conventional metallic Cu site to the acetate on the Cu atomic ensembles.

We highlight recent advances and future directions in the electrocatalytic upgrading of NO _x into value-added chemicals.