It is still a lack of bifunctional catalysts for ammonia oxidation reaction (AOR) and hydrogen evolution reaction (HER) due to their different reaction mechanisms. In this work, P is doped into PtZn alloy by calcination with NaH₂PO₂ as P source to induce the lattice tensile strain of Pt and the electronic interaction between P and Zn, which optimizes the AOR and HER activity simultaneously. The sample with the optimal P content can drive the AOR peak current density of 293.6 mA·mg_Pt⁻¹, which is almost 2.7 times of Pt. For HER, the overpotential at −10 mA·cm⁻² is only 23 mV with Tafel slope of 34.1 mV·dec⁻¹. Furthermore, only 0.59 V is needed to obtain 50 mA·mg_Pt⁻¹ for ammonia electrolysis under a two-electrode system. Therefore, this work shows an ingenious method to design bifunctional catalysts for ammonia electrolysis.

Exploiting highly active and non-noble metal bifunctional catalysts at large current density is significant for the advancement of water electrolysis. In this work, CeO₂ electronically structure modulated FeNi bimetallic composite porous nanosheets in-situ grown on nickel foam (NiFe₂O₄-Fe₂₄N₁₀-CeO₂/NF) is synthesized. Electrochemical experiments show that the NiFe₂O₄-Fe₂₄N₁₀-CeO₂/NF exhibited the outstanding activities toward both oxygen and hydrogen evolution reactions (OER and HER) (η₁₀₀₀ = 352 mV and η₁₀₀₀ = 429 mV, respectively). When assembled into a two-electrode system for overall water splitting (OWS), it only needs a low cell voltage of 1.81 V to drive 100 mA·cm⁻². And it can operate stably at ±500 mA·cm⁻² over 30 h toward OER, HER and OWS without significant activity changes. The reason could be assigned to the electronic modulating of CeO₂ on FeNi composite, which can boost the intrinsic activity and optimize the adsorption of reaction intermediates. Moreover, the porous nanosheets in-situ grown on NF could enhance the contact of active site with electrolyte and facilitate the gas release, thus improving its chemical and mechanical stabilities. This study highlights a novel approach to design bifunctional non-noble metal catalysts for water splitting at large current density.

Developing high performance anode catalysts for oxygen evolution reaction (OER) and hydrazine oxidation reaction (HzOR) at large current density is an efficient pathway to produce hydrogen. Herein, we synthesize a FeWO₄-WO₃ heterostructure catalyst growing on nickel foam (FeWO₄-WO₃/NF) by a combination of hydrothermal and calcination method. It shows good catalytic activity with ultralow potentials for OER (η₁₀ = 1.43 V, η_{1, 000} = 1.56 V) and HzOR (η₁₀ = −0.034 V, η_{1, 000} = 0.164 V). Moreover, there is little performance degradation after being tested for 100 h at 1, 000 (OER) and 100 (HzOR) mA·cm⁻², indicating good stability. The superior performance could be attributed to the wolframite structure and heterostructure: The former provides a high electrical conductivity to ensure the electronic transfer capability, and the later induces interfacial electron redistribution to enhance the intrinsic activity and stability. The work offers a brand-new way to prepare good performance catalysts for OER and HzOR, especially at large current density.