Electrochemical nitrate reduction reaction (NO₃RR) is a promising means for generating the energy carrier ammonia. Herein, we report the synthesis of heterostructure copper-nickel phosphide electrocatalysts via a simple vapor-phase hydrothermal method. The resultant catalysts were evaluated for electrocatalytic nitrate reduction to ammonia (NH₃) in three-type electrochemical reactors. In detail, the regulation mechanism of the heterogeneous Cu₃P-Ni₂P/CP-x for NO₃RR performance was systematically studied through the H-type cell, rotating disk electrode setup, and membrane-electrode-assemblies (MEA) electrolyzer. As a result, the Cu₃P-Ni₂P/CP-0.5 displays the practicability in an MEA system with an anion exchange membrane, affording the largest ammonia yield rate (R_NH3) of 1.9 mmol·h⁻¹·cm⁻², exceeding most of the electrocatalytic nitrate reduction electrocatalysts reported to date. The theoretical calculations and in-situ spectroscopy characterizations uncover that the formed heterointerface in Cu₃P-Ni₂P/CP is beneficial for promoting nitrate adsorption, activation, and conversion to ammonia through the successive hydrodeoxygenation pathway.

Here we report a vapor-phase reaction approach to fabricate rhodium(I)-dodecanethiol complex coated on carbon fiber cloth (Rh(I)-SC₁₂H₂₅/CFC), followed by low-temperature pyrolysis to achieve dodecanethiol modified Rh (Rh@SC₁₂H₂₅/CFC) for electrocatalytic nitrogen reduction reaction (NRR). The results demonstrate that after pyrolysis for 0.5 h at 150 °C, the obtained Rh@SC₁₂H₂₅/CFC-0.5 exhibits excellent NRR activity with an NH₃ yield rate of 121.2 ± 6.6 µg∙h⁻¹∙cm⁻² (or 137.7 ± 7.5 µg∙h⁻¹∙mg_Rh⁻¹) and a faradaic efficiency (FE) of 51.6% ± 3.8% at −0.2 V (vs. RHE) in 0.1 M Na₂SO₄. The theoretical calculations unveil that the adsorption of dodecanethiol on the hollow sites of Rh(111) plane is thermodynamically favorable, effectively regulating the electronic structure and surface wettability of metallic Rh. Importantly, the dodecanethiol modification on Rh(111) obviously decreases the surface H* coverage, thus inhibiting the competitive hydrogen evolution reaction and concurrently reducing the electrocatalytic NRR energy barrier.

Combining the H₂ production with brine remediation is regarded as a sustainable approach to achieving clean H₂ energy. However, designing stable Cl^- oxidation reaction (COR) electrocatalyst is the key to realize this route. Herein, a type of oxygen-modified Co nanoparticles anchored graphitic carbon nanofibers catalyst (Co/GCFs) was synthesized through a two-step strategy of adsorption and pyrolysis. The Co/GCFs-2.4 exhibits high selectivity and stability for COR at neutral electrolyte. It is worth noting that unlike the water oxidation, the chemical valence of cobalt has not changed during the COR. Further results demonstrated that the oxygen-modified Co nanoparticles provide active sites for selective COR, meanwhile, the graphitic carbon gives rise to strong catalytic stability. Thanks to the superior COR and H₂ production activity of Co/GCFs-2.4, a two-electrode brine electrocatalysis system employing Co/GCFs-2.4 as both cathode and anode for H₂ production exhibited robust stability, efficient and high Faraday efficiency (98%-100%). We propose that this work provides a novel strategy for designing efficient and stable catalysts with electrocatalytic COR and HER activities at neutral brine water for practically coupling with H₂ production by water electrolysis and brine water remediation.