Synthetic nitrogen (N) fertilizers, especially urea (CO(NH2)2) with the highest nitrogen content, nourish crop production to underpin human life. The conventional urea synthesis relies on harsh industrial processes, which consumes approximately 2% of annual global energy. Instead, electrocatalysis is an emerging sustainable technology to produce urea at ambient conditions. Herein, by directly coupling nitrate (NO3 − ) with carbon dioxide (CO2) on an indium hydroxide catalyst, we realize highly selective urea electro-synthesis at ambient conditions. We derive that CO2 can suppress adverse hydrogen evolution reaction by transforming the surface semiconducting behaviour of the model catalyst in our work.The key step of C-N coupling initiates at an early stage through the reaction of *NO2 with *CO2 intermediates owing to the low energy barrier on {100} facets, hence the subsequent urea is synthesized with high Faradaic efficiency, nitrogen selectivity, and carbon selectivity, which reach 53.4%, 82.9% and ~100%, respectively. This work offers a desirable urea synthesis route and provides deep insights into the fundamental origin of C-N coupling for guiding other sustainable synthesis of indispensable chemicals.

Developing highly efficient catalysts for oxygen evolution reaction (OER) in neutral media is extremely crucial for microbial electrolysis cells and electrochemical CO reduction. Herein, a facile one-step approach is developed to synthesize a new type of well-dispersed iridium (Ir) incorporated cobalt-based hydroxide nanosheets (nominated as CoIr) for OER. The Ir species as clusters and single atoms are incorporated into the defect-rich hydroxide nanosheets through the formation of rich Co-Ir species, as revealed by systematic synchrotron radiation based X-ray spectroscopic characterizations combining with high-angle annular dark-field scanning transmission electron microscopy measurement. The optimized CoIr with 9.7 wt% Ir content displays highly efficient OER catalytic performance with an overpotential of 373 mV to achieve the current density of 10 mA cm in 1.0 m phosphate buffer solution, significantly outperforming the commercial IrO catalysts. Further characterizations toward the catalyst after undergoing OER process indicate that unique Co oxyhydroxide and high valence Ir species with low-coordination structure are formed due to the high oxidation potentials, which authentically contributes to superior OER performance. This work not only provides a state-of-the-art OER catalyst in neutral media but also unravels the root of the excellent performance based on efficient structural identifications.

Developing highly active and low-cost heterogeneous catalysts toward overall electrochemical water splitting is extremely desirable but still a challenge. Herein, we report pyrite NiS nanosheets doped with vanadium heteroatoms as bifunctional electrode materials for both hydrogen- and oxygen-evolution reaction (HER and OER). Notably, the electronic structure reconfiguration of pyrite NiS is observed from typical semiconductive characteristics to metallic characteristics by engineering vanadium (V) displacement defect, which is confirmed by both experimental temperature-dependent resistivity and theoretical density functional theory calculations. Furthermore, elaborate X-ray absorption spectroscopy measurements reveal that electronic structure reconfiguration of NiS is rooted in electron transfer from doped V to Ni sites, consequently enabling Ni sites to gain more electrons. The metallic V-doped NiS nanosheets exhibit extraordinary electrocatalytic performance with overpotentials of about 290 mV for OER and about 110 mV for HER at 10 mA cm with long-term stability in 1 M KOH solutions, representing one of the best non-noble-metal bifunctional electrocatalysts to date. This work provides insights into electronic structure engineering from well-designed atomic defect metal sulfide.

Synthesizing urea from nitrate and carbon dioxide through an electrocatalysis approach under ambient conditions is extraordinarily sustainable. However, this approach still lacks electrocatalysts developed with high catalytic efficiencies, which is a key challenge. Here, we report the high-efficiency electrocatalytic synthesis of urea using indium oxyhydroxide with oxygen vacancy defects, which enables selective C–N coupling toward standout electrocatalytic urea synthesis activity. Analysis by operando synchrotron radiation–Fourier transform infrared spectroscopy showcases that *CO2NH2 protonation is the potential-determining step for the overall urea formation process. As such, defect engineering is employed to lower the energy barrier for the protonation of the *CO2NH2 intermediate to accelerate urea synthesis. Consequently, the defect-engineered catalyst delivers a high Faradaic efficiency of 51.0%. In conjunction with an in-depth study on the catalytic mechanism, this design strategy may facilitate the exploration of advanced catalysts for electrochemical urea synthesis and other sustainable applications.

Nonoxidative coupling of methane (NOCM) is a highly important process to simultaneously produce multicarbons and hydrogen. Although oxide-based photocatalysis opens opportunities for NOCM at mild condition, it suffers from unsatisfying selectivity and durability, due to overoxidation of CH4 with lattice oxygen. Here, we propose a heteroatom engineering strategy for highly active, selective and durable photocatalytic NOCM. Demonstrated by commonly used TiO2 photocatalyst, construction of Pd–O4 in surface reduces contribution of O sites to valence band, overcoming the limitations. In contrast to state of the art, 94.3% selectivity is achieved for C2H6 production at 0.91 mmol g–1 h–1 along with stoichiometric H2 production, approaching the level of thermocatalysis at relatively mild condition. As a benchmark, apparent quantum efficiency reaches 3.05% at 350 nm. Further elemental doping can elevate durability over 24 h by stabilizing lattice oxygen. This work provides new insights for high-performance photocatalytic NOCM by atomic engineering.

Copper-based materials can reliably convert carbon dioxide into multi-carbon products but they suffer from poor activity and product selectivity. The atomic structure-activity relationship of electrocatalysts for the selectivity is controversial due to the lacking of systemic multiple dimensions for operando condition study. Herein, we synthesized high-performance CO2RR catalyst comprising of CuO clusters supported on N-doped carbon nanosheets, which exhibited high C2+ products Faradaic efficiency of 73% including decent ethanol selectivity of 51% with a partial current density of 14.4 mA/cm−2 at −1.1 V vs. RHE. We evidenced catalyst restructuring and tracked the variation of the active states under reaction conditions, presenting the atomic structure-activity relationship of this catalyst. Operando XAS, XANES simulations and Quasi-in-situ XPS analyses identified a reversible potential-dependent transformation from dispersed CuO clusters to Cu2-CuN3 clusters which are the optimal sites. This cluster can’t exist without the applied potential. The N-doping dispersed the reduced Cun clusters uniformly and maintained excellent stability and high activity with adjusting the charge distribution between the Cu atoms and N-doped carbon interface. By combining Operando FTIR and DFT calculations, it was recognized that the Cu2-CuN3 clusters displayed charge-asymmetric sites which were intensified by CH3* adsorbing, beneficial to the formation of the high-efficiency asymmetric ethanol.

Ruthenium (Ru)‐based electrocatalysts as platinum (Pt) alternatives in catalyzing hydrogen evolution reaction (HER) are promising. However, achieving efficient reaction processes on Ru catalysts is still a challenge, especially in alkaline media. Here, the well‐dispersed Ru nanoparticles with adjacent Ru single atoms on carbon substrate (Ru1,n‐NC) is demonstrated to be a superb electrocatalyst for alkaline HER. The obtained Ru1,n‐NC exhibits ultralow overpotential (14.8 mV) and high turnover frequency (1.25 H2 s‐1 at −0.025 V vs reversible hydrogen electrode), much better than the commercial 40 wt.% Pt/C. The analyses reveal that Ru nanoparticles and single sites can promote each other to deliver electrons to the carbon substrate. Eventually, the electronic regulations bring accelerated water dissociation and reduced energy barriers of hydroxide/hydrogen desorption on adjacent Ru sites, then an optimized reaction kinetics for Ru1,n‐NC is obtained to achieve superb hydrogen generation in alkaline media. This work provides a new insight into the catalyst design in simultaneous optimizations of the elementary steps to obtain ideal HER performance in alkaline media.

MXene with unique layered structure and rich chemical compositions has been extensively investigated for lithium‐ion batteries, electrochemical capacitors, and hydrogen storage medium, but less attention has been paid to its electrocatalytic potential might due to nonideal activity. Here, an in situ growth strategy is developed to synthesize a new type of composite with carbon nanotubes (CNTs) supported on the surface of Ti3C2Tx MXene (Co/N‐CNTs@Ti3C2Tx) as bifunctional electrocatalyst toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By combining the X‐ray photoelectron detection with synchrotron‐based soft X‐ray spectroscopic characterizations, the strong interfacial coupling and electron transfer are efficiently identified, which can effectively facilitate the bifunctional electrocatalytic performance of Co/N‐CNTs@Ti3C2Tx toward ORR and OER in alkaline solution. The present strategy provides a facile route for the design of the hybrids of CNTs and MXene for bifunctional electrocatalysis.