Single-atom platinum with asymmetric coordination environment on fully conjugated covalent organic framework for efficient electrocatalysis

Abstract

Two-dimensional (2D) covalent organic frameworks (COFs) and their derivatives have been widely applied as electrocatalysts owing to their unique nanoscale pore configurations, stable periodic structures, abundant coordination sites and high surface area. This work aims to construct a non-thermodynamically stable Pt-N2 coordination active site by electrochemically modifying platinum (Pt) single atoms into a fully conjugated 2D COF as conductive agent-free and pyrolysis-free electrocatalyst for the hydrogen evolution reaction (HER). In addition to maximizing atomic utilization, single-atom catalysts with definite structures can be used to investigate catalytic mechanisms and structure-activity relationships. In this work, in-situ characterizations and theoretical calculations reveal that a nitrogen-rich graphene analogue COF not only exhibits a favorable metal-support effect for Pt, adjusting the binding energy between Pt sites to H* intermediates by forming unique Pt-N2 instead of the typical Pt-N4 coordination environment, but also enhances electron transport ability and structural stability, showing both conductivity and stability in acidic environments.

ZIF-67-Derived Porous Carbon Nanosheets Decorated with Co Nanoflakes As Bifunctional Electrocatalysts for Overall Water Splitting

“…As demonstrated in Figures d and S10, Co@NC/CC-500 has the largest C dl value (72.69 mF cm –2 ), indicating more active sites than other samples, which corresponds to the highest intrinsic OER activity. In order to evaluate the intrinsic OER activity of the Co@NC/CC-500 catalyst, the calculation of turnover frequency (TOF) , of Co@NC/CC-500 was performed, and the result is 7.73 S 1– . The calculation of the TOF is described in the Supporting Information.…”