Non-Noble Metal-Based NiFeMoS _<i>x</i> Hollow Nanocubes Enable Fast and Selective Hydrogen Sensing at Moderate Temperature

Ensuring safety in the expanding use of hydrogen fuel cells and lithium-ion batteries requires reliable, selective, and low-power H2 detection. However, conventional chemo-resistive hydrogen (H2) sensors often rely on noble metals operating at high temperatures, limiting their cost-efficiency and scalability. Here, we present an enzyme-inspired, non-noble metal, moderate operating temperature hydrogen sensor based on hollow NiFeMoSx nanocubes, synthesized via a hydrothermal transformation of Ni–Fe Prussian blue analogues with (NH4)2MoS4. Mimicking the catalytic [NiFeS] clusters in natural hydrogenases, the engineered hollow nanocubes exhibit exceptional H2 selectivity and rapid response/recovery (28 s/29 s) at 500 ppm at a moderate operating temperature (∼80 °C). The enhanced sensing performance is attributed to the synergistic effects of bioinspired [NiFeS] active sites, the high surface area of the hollow structure, and the improved electron transport facilitated by Mo–S integration. This work provides a sustainable and scalable strategy for constructing non-noble, high-performance H2 sensors for next-generation energy safety systems.