Electrocatalytic nitrate reduction reaction (eNO₃RR) presents an innovative approach to achieve green NH₃ synthesis and mitigate environmental NO₃⁻ pollution. However, the bottleneck for large-scale application of eNO₃RR is the development of efficient electrocatalysts. Herein, inspired by the structure of nitrogenase and nitrate reductase, a novel Fe-Mo-based electrocatalyst (FeMoS-O) with distinctive bimetallic Fe-O-Mo active centers was developed using FeMo₂S₄ as the precursor via in situ electrochemical activation to induce surface O-doping. Combining comprehensive in situ characterizations and theoretical calculation results reveal that the Fe and Mo sites of the Fe-O-Mo center are responsible for the hydrogenation of NO_x species and the dissociation of H₂O, respectively, which is similar to the working mechanism of nitrate reductase. Meanwhile, O-doping on the Fe-O-Mo surface significantly reduces the energy barriers of the rate-determining steps of these two processes. As feedback, the synergistic effect of Mo and Fe sites endows the resultant FeMoS-O with excellent eNO₃RR performance under neutral conditions, with high faradaic efficiency (> 90%) in a potential window exceeding 0.50 V, large partial current density and yields, as well as quite good stability towards NH₃ production. This work provides new insights into the preparation of more advanced enzyme-mimicking catalysts.

Metal-free carbon catalysts are promising alternatives to noble-metal electrocatalysts for H₂O₂ production through two electron oxygen reduction reaction (2e⁻ ORR). Herein, a novel bioengineering approach is proposed to prepare N-doped hollow carbon nanoboxes from guanine precursor. The optimized NC-HNBs-550 exhibits an exceptional electrocatalytic performance, achieving a high H₂O₂ Faradaic efficiency (FE) of over 90% across a broad potential window exceeding 0.6 V. Remarkably, when tested in a flow cell configuration, NC-HNBs-550 delivers near-unity FE for H₂O₂ production at industrial-grade current densities, demonstrating its practicality for scalable applications. Impressively, the in situ electro-synthesized H₂O₂ is further employed as a green oxidant for rapid degradation of various organic dyes and even tetracyclines, and high-purity benzoyl peroxide (BPO) synthesis, highlighting its versatility in environmental and chemical applications. Combining experimental and theoretical analyses, we reveal that the superior 2e⁻ ORR activity originates from the abundance of pyrrolic-N species in NC-HNBs, which optimize the adsorption energy of *OOH intermediates and promote selective O₂ reduction. This work not only advances the rational design of biomass-derived carbon catalysts for sustainable H₂O₂ production but also provides a versatile platform for environmental remediation and value-added chemical production.

The influence of nitrogen dopants on the catalytic activity of carbon-based materials has been studied extensively, but the exact role of nitrogen species in these materials remains unclear. A challenge in understanding the role of nitrogen is that most nitrogen-doped nanocarbon (NC) materials are dominated by uncontrollable surface functional groups, and changes in nitrogen species often lead to variations in oxygen functional groups, which makes the specific role of nitrogen difficult to isolate. To address this issue, we developed a series of NCs containing variable types and contents of nitrogen (5–30 at.%) and a constant oxygen content of approximately 4 at.%. Results show that the different types of nitrogen in the NCs, namely, graphitic nitrogen and pyridinic nitrogen, serve as electron-donating and -withdrawing modulators, respectively, and can tailor the oxidative dehydrogenation activity of the NCs. Additionally, graphitic nitrogen plays a role in mediating frustrated Lewis pairs consisting of pyridinic nitrogen and neighboring carbon atoms. These pairs are responsible for the activation of hydrogen–hydrogen bonds, which is the rate-determining step in nitrobenzene hydrogenation.

The development of highly selective, cost-effective, and energy-efficient electrocatalysts is critical for carbon dioxide reduction reaction (CO₂RR) to produce high-value products. Herein, we propose a facile strategy to obtain F, N co-doped carbon-coated iron carbide (Fe₃C) nanoparticles by using biomolecule guanine and hexadecafluorophthalocyanine iron as raw materials. Remarkably, this method involves only one-step pyrolysis and does not require any guiding agent or sacrificial template. Benefiting from the advantageous surface microenvironment adjustments achieved through graphitic N (G_N) and F co-doping, Fe₃C@NF-G-1000 demonstrates exceptional efficacy in the electroreduction of CO₂ to carbon monoxide (CO) with an impressive Faradic efficiency (FE_co) up to 98% at the potential of −0.55 V (vs. reversible hydrogen electrode (RHE)). Furthermore, it delivers a remarkable current density of up to −43 mA·cm⁻² and exhibits virtually no current attenuation over a span of 20 h within the flow cell. Insights from density functional theory (DFT) calculations reveal that the composite structure of G_N and F co-doped graphitic layer and Fe₃C exhibits different electron density distributions from that of iron carbide nanoparticles. This is attributed to the synergistic effect of the composite structure leading to the enrichment of electrons in the graphite layer on the surface, which contributes to the stability of the key reaction intermediate *COOH, thus, resulting in an enhanced catalytic activity and efficiency. Overall, this work introduces a new and promising approach to the design of green and low-cost carbon-coated metal materials for CO₂ reduction reactions.