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Photocatalytic organic functionalization reactions represent a green, cost‐effective, and sustainable synthesis route for value‐added chemicals. However, heterogeneous photocatalysis is inefficient in directly activating ammonia molecules for the production of high‐value‐added nitrogenous organic products when compared with oxygen activation in the formation of related oxygenated compounds. In this study, we report the heterogeneous photosynthesis of benzonitriles by the ammoxidation of benzyl alcohols (99 % conversion, 93 % selectivity) promoted using BiOBr nanosheets with surface vacancy associates. In contrast, the main reaction of catalysts with other types of vacancy sites is the oxidation of benzyl alcohol to benzaldehyde or benzoic acid. Experimental measurements and theoretical calculations have demonstrated a specificity of vacancy type with respect to product selectivity, which arises from the adsorption and activation of NH3 and O2 that is required to promote subsequent C−N coupling and oxidation to nitrile. This study provides a better understanding of the role of vacancies as catalytic sites in heterogeneous photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Ni/NiFe-LDO was prepared via a phase-transition and in-situ reduction method. • The Ni/NiFe-LDO shows Pt-like activity for HER (29 mV at 10 mA cm−2). • Synergistic effect between nano-Ni and NiFe-LDO is key to superior performance. • Two-dimensional structure of NiFe-LDO can stabilize in-situ formed nano-Ni sites. • Fe 2 O 3 boosts the adsorption of H 2 O molecule which is benefit for water activation. High-performance, cost-effective and stable electrocatalysts are critical for hydrogen evolution reaction (HER) via water splitting in alkaline media. Herein a unique hetero-nanostructured Ni/NiFe-layered double oxide (Ni/NiFe-LDO) on Ni foam (NF) has been successfully constructed through phase-transition and controlled in-situ reduction process. Because the two-dimensional (2D) morphology of NiFe-LDO nanosheets can stabilize uniform in-situ formed nano-Ni sites, the prepared Ni/NiFe-LDO on NF displays a high catalytic activity for HER in 1.0 M KOH solution, which requires an extremely low overpotential of 29 mV to afford a current density at 10 mA cm−2, achieves a Tafel slope of 82 mV dec-1 and maintains an excellent stability of electrolysis for at least 24 h. Detail characterizations reveal that the synergistic effect between nano-Ni and NiFe-LDO nanosheets contributes to the prominent HER activity. In NiFe-LDO, Fe 2 O 3 facilitates the adsorption of H 2 O on the interface region of Ni-Fe 2 O 3 , which is beneficial for water activation, then NiO offers the active sites for hydroxyl adsorption (*OH), meanwhile nano-Ni sites are active to adsorb hydrogen intermediates (H*). All of the above accelerates the water dissociation in Volmer-step reaction. [ABSTRACT FROM AUTHOR]