Cation vacancy stabilization of single-atomic-site Pt1/Ni(OH)x catalyst for diboration of alkynes and alkenes

Abstract

Development of single-atomic-site catalysts with high metal loading is highly desirable but proved to be very challenging. Although utilizing defects on supports to stabilize independent metal atoms has become a powerful method to fabricate single-atomic-site catalysts, little attention has been devoted to cation vacancy defects. Here we report a nickel hydroxide nanoboard with abundant Ni2+ vacancy defects serving as the practical support to achieve a single-atomic-site Pt catalyst (Pt1/Ni(OH)x) containing Pt up to 2.3 wt% just by a simple wet impregnation method. The Ni2+ vacancies are found to have strong stabilizing effect of single-atomic Pt species, which is determined by X-ray absorption spectrometry analyses and density functional theory calculations. This Pt1/Ni(OH)x catalyst shows a high catalytic efficiency in diboration of a variety of alkynes and alkenes, yielding an overall turnover frequency value upon reaction completion for phenylacetylene of ~3000 h−1, which is much higher than other reported heterogeneous catalysts.

Achieving Efficient Alkaline Hydrogen Evolution Reaction over a Ni5P4 Catalyst Incorporating Single‐Atomic Ru Sites

“…A strong Ru 3+ EPR signal was detected for V‐Ni(OH) 2 ‐Ru; however, no obvious Ru 3+ signal could be seen for P‐Ni(OH) 2 ‐Ru (Figure S3a, Supporting Information) . As expected, the stabilization of Ru cations by nickel vacancies has occurred, which could be attributed to the electronic coupling mechanism . It is well established that the coupling would induce the local structural perturbance in the interfaces.…”

Defect‐Based Single‐Atom Electrocatalysts

“…For example, Wang and co‐workers have summarized the recent exciting findings of defects in catalysts for oxygen reactions and explained the effects of defects on the electrocatalytic performance . In addition to the electrochemical reactions activated by the defects themselves, the defects are also used to provide unique anchor sites for the capture of metal species . Inspired by the recent research findings, we discover that the interesting combination of defects and single metal atoms can achieve well stability and high activity of SACs, that is, the defects and SACs can collaboratively promote the catalytic activity .…”

“…Recently, Wang et al recently achieved a single catalyst with Pt loading up to 2.3 wt% supported on Ni(OH) 2 nanoboards with rich Ni 2+ vacancy defects (Pt 1 /Ni(OH) x ) . The single Pt atom anchored on the Ni(OH) 2 with Ni 2+ vacancies displayed a much lower formation energy than that of Pt/Ni(OH) 2 without Ni 2+ vacancies ( Figure A,B), indicating the strong electron interaction between Ni 2+ vacancies and isolated Pt atoms.…”

“…C) Fourier transform EXAFS spectrum of the Pt 1 /Ni(OH) x catalyst. Reproduced with permission . Copyright 2018, Nature Publishing Group.…”

Single Metal Atom Photocatalysis

“…Apart from surface step edges, cation vacancies have been exploited as anchoring sites for single metal atoms. In the Pt 1 /Ni(OH) x catalyst with high Pt loading (2.3 wt%), it was found that abundant Ni vacancies on the surface of Ni(OH) x nanoboard served as anchoring sites to trap the single Pt atoms . Qiao et al reported that Au 1 atoms likely occupied the Ce vacancy sites of CeO 2 nanocrystal, as evidenced by the atomic‐resolution high‐angle annular dark‐field scanning transmission electron microscope (HAADF‐STEM) images .…”