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Hydroxylamine (NH2OH) is an important feedstock in fuels, pharmaceuticals, and agrochemicals. Nanostructured electrocatalysts drive green electrosynthesis of hydroxylamine from nitrogen oxide species in water. However, current electrocatalysts still suffer from low selectivity and manpower‐consuming trial‐and‐error modes, leaving unclear selectivity/activity origins and a lack of catalyst design principles. Herein, we theoretically analyze key determinants of selectivity/activity and propose the adsorption energy of NHO (Gad(*NHO)) as a performance descriptor. A weak *NH2OH binding affinity and a favorable reaction pathway (*NHO pathway) jointly enable single‐atom catalysts (SACs) with superior NH2OH selectivity. Then, an activity volcano plot of Gad(*NHO) is established to predict a series of SACs and discover Mn SACs as optimal electrocatalysts that exhibit pH‐dependent activity. These theoretical prediction results are also confirmed by experimental results, rationalizing our Gad(*NHO) descriptor. Furthermore, Mn−Co geminal‐atom catalysts (GACs) are predicted to optimize Gad(*NHO) and are experimentally proved to enhance NH2OH formation. [ABSTRACT FROM AUTHOR]

NiFe 2 O 4 is a promising sensing material for acetone detection, in which synthesizing 1D nanostructure and modulating the chemical composition are efficient strategies to enhance the sensing properties for multiple applications in reality. Herein, 1D precursor is hydrothermally synthesized using nitrilotriacetic acid (NTA) to chelate Fe3+ and Ni2+ ions. After thermal annealing, nanoparticles assembled 1D NiFe 2 O 4 nanorods with mesoporous structures are prepared. The porous 1D structure yields a large surface area (197.1 m2/g), exposes more active sites as well as offers a suitable backbone for Pt nanoparticles functionalization, facilitating acetone detection. The gas sensor based on Pt functionalized NiFe 2 O 4 nanorods exhibits high response of 48.2–100 ppm acetone at 160 °C with a rapid response and recovery time (10 s/26 s), low limits of detection (1 ppm), good selectivity, outstanding repeatability and reliable long-term durability (30 days). In addition, a good linearity of the response as a function of the acetone concentration from 1 to 200 ppm is fitted. These results may open a novel avenue to fabricate mesoporous 1D NiFe 2 O 4 that is an extremely promising candidate for acetone detection. [Display omitted] • Mesoporous 1D NiFe 2 O 4 nanorods were synthesized using nitrilotriacetic acid followed by thermal treatment. • The NiFe 2 O 4 nanorods are assembled by nanoparticles, exhibiting a surface area of 197.1 m2/g. • The NTA contents exert influence on the morphologies and the sensing properties of NiFe 2 O 4. • The sensing performance of mesoporous NiFe 2 O 4 nanorods is enhanced by Pt functionalization. [ABSTRACT FROM AUTHOR]