Facile and large‐scale preparation of materials with uniform distributions of ultrafine particles for catalysis is a challenging task, and it is even more difficult to obtain catalysts that excel in both the hydrogen evolution reaction (HER) and hydrogenation, which are the corresponding merging and splitting procedures of hydrogen, respectively. Herein, the fabrication of ultrafine bimetallic PtNi nanoparticles embedded in carbon nanosheets (CNS) by means of in situ self‐polymerization and annealing is reported. This bifunctional catalyst shows excellent performance in the hydrogen evolution reaction (HER) and the hydrogenation of p‐nitrophenol. Remarkably PtNi bimetallic catalyst with low metal loading (PtNi2@CNS‐600, 0.074 wt % Pt) exhibited outstanding HER activity with an overpotential as low as 68 mV at a current density of 10 mA cm−2 with a platinum loading of only 0.612 μgPt cm−2 and Tafel slope of 35.27 mV dec−1 in a 0.5 m aqueous solution of H2SO4, which is comparable to that of the 20 % Pt/C catalyst (31 mV dec−1). Moreover, it also shows superior long‐term electrochemical durability for at least 30 h with negligible degradation compared with 20 % Pt/C. In addition, the material with increased loading (mPtNi2@CNS‐600, 2.88 % Pt) showed robust catalytic activity for hydrogenation of p‐nitrophenol at ambient pressure and temperature. The catalytic activity towards hydrogen splitting is a circumstantial evidence that agrees with the Volmer–Tafel reaction path in the HER.

Modifying the surface of metal catalyst is a crucial subject for improving the heterogeneous metal catalysts. It is still a great challenge to understand the structure‐activity relationship (SAR) between the surface supporting groups and the metal particles. Herein, Rh NPs supported on the magnetic silica sphere with various functional groups (−NH2, −SH, −SO3H, −N=CH2, −Cl, −NHCOCH3 and −NHCH2Ph) have been prepared for catalytic hydrogenation of nitroarenes under atmospheric pressure at room temperature. We discover that the chemical state of Rh NPs depends on the supporting groups significantly. The electron‐donating functionalities can effectively elevate the Rh0/Rh3+ ratio, which increase the catalytic performance both in conversion and selectivity. The amino group decorated catalyst has such a good selectivity that no dechlorination reaction is observable in the hydrogenation of 2‐chloro‐3‐nitropyridine. What's more, by introducing magnetic Fe3O4 nuclei and mesoporous silica encapsulating layer, the catalyst can be recovered conveniently by an external magnet, and can be reused 10 cycles without any loss of activity.

Cascade reactions take advantage of step-saving and facile operation for obtaining chemicals. Herein, catalytic hydrogenation of nitroarene coupled condensation with β-diketone to afford β-ketoenamines is achieved by an integrated nanocatalyst, Pd-e@UiO-66. The catalyst has the structure of an acid-rich metal–organic framework (MOF), UiO-66-encapsulated electron-rich Pd nanoparticles, and it reconciles the electron-effect contradiction of cascade catalytic reactions: catalytic hydrogenation requires an electron-rich catalyst, while condensation requires electron-deficient Lewis acid sites. The catalyst showed good activity, high chemoselectivity, and universal applicability for the synthesis of β-ketoenamines using nitroarenes. More than 30 β-ketoenamines have been successfully prepared with up to 99% yield via the methodology of relay catalysis. The catalyst exhibited excellent stability to maintain its catalytic performance for more than five cycles. Furthermore, we conducted an in-depth exploration of the reaction mechanism with theoretical calculations.

The chemoselective hydrogenation to afford functionalized amines is a challenging task in the field of applied catalysis. In this work, we constructed a versatile catalytic system for the nondestructive hydrogenation of nitro and cyano group to afford the functionalized aromatic and primary amines under mild conditions. The dilemma of effects on other sensitive functional groups in the hydrogenation is solved by the precisely controlled activity from the trace palladium alloying with copper in our catalyst. The TOF achieved 5376 h−1 and 322581 h−1 for Pd when the functionalized nitriles and nitroarenes were used as substrate respectively. In a word, the good compatibility and recyclability, the mild operation conditions, extremely low consumption of noble metal, ppm level Pd, and economically available hydrogen donor, HCOOH, highlight the contribution of this work.

Various precious metal catalysts have been commonly used in catalytic reactions, but the differences and likeness between their catalytic performances are rarely systematically studied. Therefore, we have prepared the Pd, Pt, Rh, Ru, Au, and Ag/ Fe 3 O 4 catalysts, and the similarities and differences of various catalysts are analyzed by XRD, FT-IR, TEM, HR-TEM, XPS, BET, and VSM characterizations. Besides that platinum is the best catalyst component, the Pd and Rh/Fe 3 O 4 catalysts also exhibit excellent catalytic activity and chemoselectivity, but the Ru, Au, Ag-containing catalysts show poor catalytic performance for hydrogenation of 4-nitrophenol. According to the kinetic study, we have demonstrated that the reaction orders for Pd, Pt, and Rh are 0.8, 0.8, and 1.5, respectively. This result reveals that the activity of Pd, Pt, and Rh-containing catalysts can be precisely predicted. Moreover, our catalytic system is fascinating with many advantages such as environmental friendliness, mild reaction conditions, and the magnetic separability.[a] Dr. differences in their catalytic activity. Moreover, the TOF of the Pd, Pt, and Rh-containing catalysts is precisely predicable with the palladium, platinum, and rhodium content, and their predictable activity models can be built. Our catalytic system has unparalleled advantages with environmentally friendly, mild reaction conditions (low temperature and atmospheric H 2 pressure), and the magnetic separability. Furthermore, all of the Pd, Pt, and Rh-containing catalysts show outstanding reusability with at least 5 cycles. 2 3 4 5 6 7 8