The product selectivity in catalytic hydrogenation of nitriles is strongly correlated with the structure of the catalyst. In this work, two types of atomically dispersed Pd species stabilized on the defect-rich nanodiamond-graphene (ND@G) hybrid support: single Pd atoms (Pd₁/ND@G) and fully exposed Pd clusters with average three Pd atoms (Pd_n/ND@G), were fabricated. The two catalysts show distinct difference in the catalytic transfer hydrogenation of nitriles. The Pd₁/ND@G catalyst preferentially generates secondary amines (Turnover frequency (TOF@333 K 709 h⁻¹, selectivity >98%), while the Pd_n/ND@G catalyst exhibits high selectivity towards primary amines (TOF@313 K 543 h⁻¹, selectivity >98%) under mild reaction conditions. Detailed characterizations and density functional theory (DFT) calculations show that the structure of atomically dispersed Pd catalysts governs the dissociative adsorption pattern of H₂ and also the hydrogenation pathway of the benzylideneimine (BI) intermediate, resulting in different product selectivity over Pd₁/ND@G and Pd_n/ND@G, respectively. The structure-performance relationship established over atomically dispersed Pd catalysts provides valuable insights for designing catalysts with tunable selectivity.

A core–shell structured nanocatalyst (Fe₃O₄@SiO₂-NH₂-RhNPs@mSiO₂) that is encapsulated with porous silica has been designed and prepared for catalyzing the transfer hydrogenation of nitro compounds into corresponding amines. Rh nanoparticles serve as the activity center, and the porous silica shell plays an important role in the “slow-release” of the hydrogen source hydrazine. This reaction can be carried out smoothly in the green solvent water, and the atom economy can be improved by decreasing the amount of hydrazine hydrate used to a stoichiometric 1.5 equivalent of the substrate. Significantly, high catalytic efficiency is obtained and the turnover frequency (TOF) can be up to 4373 h⁻¹ in the reduction of p-nitrophenol (4-NP). A kinetics study shows that the order of reaction is ∼0.5 towards 4-NP, and the apparent active energy E_a is 58.18 kJ mol⁻¹, which also gives evidence of the high catalytic efficiency. Additionally, the excellent stability of the catalyst has been verified after 15 cycles without any loss of catalytic activity, and it is easily recovered by a magnet after reaction due to the Fe₃O₄ nucleus.

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Devising an electrocatalyst with brilliant efficiency and satisfactory durability for hydrogen production is of considerable demand, especially for large-scale application. Herein, we adopt a multi-step consequential induced strategy to construct a bifunctional electrocatalyst for the overall water splitting. Graphene oxide (GO) was used as a carbon matrix and in situ oxygen source, which was supported by the octahedral PtNi alloy to form the Pt_xNi_y-GO precursor. When calcinating in Ar atmosphere, the oxygen in GO induced the surface segregation of Ni from the PtNi octahedron to form a core-shell structure of Pt_x@Ni_y. Then, the surface-enriched Ni continuously induced the reformation of C in reduced graphene oxide (rGO) to enhance the degree of graphitization. This multi-step induction formed a nanocatalyst Pt_x@Ni_y-rGO which has very high catalytic efficiency and stability. By optimizing the feeding ratio of PtNi (Pt:Ni = 1:2), the electrolytic overall water splitting at 10 mA·cm⁻² can be driven by an electrolytic voltage of as low as 1.485 V, and hydrogen evolution reaction (HER) only needs an overpotential of 37 mV in 1.0 M KOH aqueous solution. Additionally, the catalyst exhibited consistent existence form in both HER and oxygen evolution reaction (OER), which was verified by switching the anode and cathode of the cell in the electrolysis of water. This work provides a new idea for the synthesis and evaluation of the bifunctional catalysts for water splitting.