Alloying at a Subnanoscale Maximizes the Synergistic Effect on the Electrocatalytic Hydrogen Evolution

Abstract

Bonding dissimilar elements to provide synergistic effects is an effective way to improve the performance of metal catalysts. However, as the properties become more dissimilar, achieving synergistic effects effectively becomes more difficult due to phase separation. Here we describe a comprehensive study on how subnanoscale alloying is always effective for interelemental synergy. Thirty-six combinations of both bimetallic subnanoparticles (SNPs) and nanoparticles (NPs) were studied systematically using atomic-resolution imaging and catalyst benchmarking based on the hydrogen evolution reaction (HER). Results revealed that SNPs always produce greater synergistic effects than NPs, the greatest synergistic effect was found for the combination of Pt and Zr. The atomic-scale miscibility and the associated modulation of electronic states at the subnanoscale were much different from those at the nanoscale, which was observed by annulardark-field scanning transmission electron microscopy (ADF-STEM) and X-ray photoelectron spectroscopy (XPS), respectively.

Bimetallic Sites for Catalysis: From Binuclear Metal Sites to Bimetallic Nanoclusters and Nanoparticles

“…Following this concept, bimetallic PtZr nanoclusters with different Pt/Zr ratios, and particle sizes are generated by controlling the pulses of arcplasma deposition and then tested for electrocatalytic HER. 438 As shown in Figure 44, the Pt 4 Zr 2 sample (prepared by four pluses of Pt and two pulse of Zr deposition) comprising PtZr nanoclusters of ∼0.8 nm delivers the best activity. The significant promotion effect of Zr to Pt for electrocatalytic HER can be explained by the modification of the electronic feature of Pt, which weakens the adsorption of Pt−H species.…”

“…HER synergistic index (HSI) was defined by the following formula: HIS = (2 i 0 (M 1 x M 2 y ) – i 0 (M 1 x ) – i 0 (M 2 y ))/2 i 0 (M 1 x M 2 y )), where i 0 (M 1 ), i 0 (M 2 ), and i 0 (M 1 x M 2 y ) represent the HER exchange current of single component M 1 , single component M 2 , and bimetallic M 1 x M 2 y ( x and y represent concentrations of M 1 and M 2 , respectively). Reproduced with permission from ref . Copyright 2022 Wiley-VCH.…”

“…In order to clarify the impacts of the chemical composition of bimetallic nanoclusters in catalytic reactions, the comparative study should be performed on a series of model catalysts derived from the same sample preparation method. Following this concept, bimetallic PtZr nanoclusters with different Pt/Zr ratios, and particle sizes are generated by controlling the pulses of arcplasma deposition and then tested for electrocatalytic HER . As shown in Figure , the Pt 4 Zr 2 sample (prepared by four pluses of Pt and two pulse of Zr deposition) comprising PtZr nanoclusters of ∼0.8 nm delivers the best activity.…”

Reasonably constructed nano-alloyed materials as highly efficient electrocatalysts for the hydrogen evolution reaction

“…In order to improve the intrinsic activity of catalysts, composition tuning of materials is an effective strategy to improve the catalytic performance. For alloy material systems, the current research on composition regulation mainly focuses on the synergistic effect (including the synergistic effect between metals, 23,26,27,31,32,34,35,49,50,132–135 alloys and carriers, 54–57,79,80,130,131 and alloys and structures) 92,136–138 doping effect 61,95,97,98,139–142 and multisite effect. 64–72,99–103,143…”

Regulating Ru active sites by Pd alloying to significantly enhance hydrazine oxidation for energy-saving hydrogen production

“…30 Comparatively, bimetallic alloy catalysts oen exhibit markedly intensied activity relative to the mono-metallic analogues, because of the synergistic strain and/or electronic effect. [31][32][33] Meanwhile, the alloy can be also potentially endowed with a bifunctionality arising from the intermixed components with the welltailored physicochemical properties. 31,34,35 On the other hand, to maximize the efficacy of catalysts, the ne dispersity of naked noble metals without capping agents is compulsory, and it can be delicately achieved by immobilizing metals on eligible carbonaceous supports, which can also afford additionally high surface area and benign electricity.…”