Ammonia oxidation reaction (AOR) offers a promising carbon-free hydrogen production pathway under ambient conditions, yet practical implementation faces critical challenges from catalyst deactivation and competing side reactions in aqueous systems. We present an electrolyte-engineered approach to photoelectrochemical (PEC) AOR that enables both enhanced hydrogen production and reversible catalyst regeneration. By employing a non-aqueous acetonitrile electrolyte at the BiVO4 photoanode, we suppress competing oxygen evolution and NOx poisoning, achieving a 6.9-fold higher hydrogen yield than aqueous systems. Spectroscopic and electrochemical analyses reveal that catalyst deactivation in water is not permanent but dynamically reversible upon re-exposure to non-aqueous environment, emphasizing the solvent-governed interfacial behavior. This electrolyte-engineering approach proves broadly applicable across metal oxide photoanodes (BiVO4, WO3, α-Fe2O3), establishing a universal design principle for PEC AOR systems. Our findings redefine the role of electrolyte composition in governing interfacial pathways and provide a practical framework for developing high-efficiency ammonia-to-hydrogen conversion platforms with enhanced durability and flexibility.

Metal hydrides are promising materials for storing, compressing, and purifying hydrogen by reversibly absorbing and releasing it. Accurate first-principles based prediction of the pressure–composition–temperature (PCT) relationships of metal hydrides can enable predictive optimization of hydrogen capacity and sorption pressures. In this work, we introduce a novel computational framework that integrates density functional theory (DFT) with a Python-based PCT Simulation Toolkit to predict PCT diagrams with high accuracy. By using only structural input data from the metallic phase, this toolkit automates the detection of interstitial voids, generates input files for DFT calculations, and constructs thermodynamic models based on para-equilibrium principles. We validate this approach across four major metal hydride classes– BCC alloys, AB5, AB2, and AB compounds– and demonstrate that even with minimal computational effort, key hydrogen sorption characteristics can be reliably determined. To evaluate the influence of exchange and correlation, we tested three different functionals– PBE, PW91, and r2SCAN– while applying the quasi-harmonic approximation to incorporate vibrational free energy contributions. Our results show that hydrogen capacity predictions achieve a mean accuracy of 95%, while sorption pressures are modeled within one order of magnitude of experimental values. Furthermore, we successfully extend this methodology to the BCC NbTiV multicomponent system, demonstrating its capability to construct comprehensive thermodynamic databases. This framework enables rapid and accurate exploration of known metal hydrides to design optimized alloys for new applications. Additionally, it serves as a predictive tool for designing novel hydrogen storage materials.

Molybdenum disulfide holds promise as a low cost and abundant catalyst for the hydrogen evolution reaction in an alkaline environment. However, its hydrogen evolution reaction activity is not sufficient for practical application because of its semiconducting properties in the 2H phase, presence of an electrochemically inert basal plane, and suboptimal hydrogen adsorption energy for hydrogen evolution reaction. In this article, we present a facile synthesis method for fabricating a Ni-doped molybdenum disulfide hydrogen evolution reaction electrode with a 1T structure through co-sputtering of molybdenum disulfide and Ni. Our results demonstrate that Ni doping not only promotes the 1T-phase yield in molybdenum disulfide structure but also activates the basal plane and improves the hydrogen adsorption energy of the edge plane. Also, the surface morphologies and 1T-phase yield, which are influenced by sputtering power and deposition time, are critical factors for the variation of hydrogen evolution reaction performance. Our Ni-doped molybdenum disulfide electrode, which exhibits high 1T yield and increased electrochemical surface area by tuning the morphology, shows an overpotential of ~91 mV at 10 mA cm−2, nearly 2.5 times lower than that of ~227 mV observed for molybdenum disulfide. Also, the single-cell test exhibits enhanced cell performance with improved durability in the repetitive on/off evaluation for the potential application of renewable energy integration.