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1.
Mater Horiz ; 10(8): 2913-2920, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37158051

RESUMO

Pt-based nanoclusters toward the hydrogen evolution reaction (HER) remain the most promising electrocatalysts. However, the sluggish alkaline Volmer-step kinetics and the high-cost have hampered progress in developing high-performance HER catalysts. Herein, we propose to construct sub-nanometer NiO to tune the d-orbital electronic structure of nanocluster-level Pt for breaking the Volmer-step limitation and reducing the Pt-loading. Theoretical simulations firstly suggest that electron transfer from NiO to Pt nanoclusters could downshift the Ed-band of Pt and result in the well-optimized adsorption/desorption strength of the hydrogen intermediate (H*), therefore accelerating the hydrogen generation rate. NiO and Pt nanoclusters confined into the inherent pores of N-doped carbon derived from ZIF-8 (Pt/NiO/NPC) were designed to realize the structure of computational prediction and boost the alkaline hydrogen evolution. The optimal 1.5%Pt/NiO/NPC exhibited an excellent HER performance and stability with a low Tafel slope (only 22.5 mv dec-1) and an overpotential of 25.2 mV at 10 mA cm-2. Importantly, the 1.5%Pt/NiO/NPC possesses a mass activity of 17.37 A mg-1 at the overpotential of 20 mV, over 54 times higher than the benchmark 20 wt% Pt/C. Furthermore, DFT calculations illustrate that the Volmer-step could be accelerated owing to the high OH- attraction of NiO nanoclusters, leading to the Pt nanoclusters exhibiting a balance of H* adsorption and desorption (ΔGH* = -0.082 eV). Our findings provide new insights into breaking the water dissociation limit of Pt-based catalysts by coupling with a metal oxide.

2.
Nanoscale Adv ; 3(17): 5062-5067, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-36132342

RESUMO

Pt3Sn nanoparticles (NPs) enriched with Pt3Sn/ultra-small SnO2 interfaces (Pt3Sn@u-SnO2/NG) were synthesized through a thermal treatment of Pt2Sn/NG in a H2 atmosphere, followed by annealing under H2 and air conditions. The unique structure of Pt3Sn NPs enriched with Pt3Sn/SnO2 interfaces was observed on the Pt3Sn@u-SnO2/NG catalyst based on HRTEM. The optimized Pt3Sn@u-SnO2/NG catalyst achieves high catalytic activity with an ethanol oxidation reaction (EOR) activity of 366 mA mgPt -1 and a methanol oxidation reaction (MOR) activity of 503 mA mgPt -1 at the potential of 0.7 V, which are eight-fold and five-fold higher than those for the commercial Pt/C catalyst (44 and 99 mA mgPt -1, respectively). The Pt3Sn@u-SnO2/NG catalyst is found to be 3 times more stable and have higher CO tolerance than Pt/C. The outstanding performance of the Pt3Sn@u-SnO2/NG catalyst should be ascribed to the synergetic effect induced by the unique structure of Pt3Sn NPs enriched with Pt3Sn/SnO2 interfaces. The synergetic effect between Pt3Sn NPs and ultra-small SnO2 increases the performance for alcohol oxidation because the Sn in both Pt3Sn and SnO2 favors the removal of COads on the nearby Pt by providing OHads species at low potentials. The present work suggests that the Pt3Sn@u-SnO2 is indeed a unique kind of efficient electrocatalyst for alcohol electrooxidation.

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