Selective CO₂ reduction to CH₃OH over atomic dual-metal sites embedded in a metal-organic framework with high-energy radiation.

Abstract

The efficient use of renewable X/γ-rays or accelerated electrons for chemical transformation of CO₂ and water to fuels holds promise for a carbon-neutral economy; however, such processes are challenging to implement and require the assistance of catalysts capable of sensitizing secondary electron scattering and providing active metal sites to bind intermediates. Here we show atomic Cu-Ni dual-metal sites embedded in a metal-organic framework enable efficient and selective CH₃OH production (~98%) over multiple irradiated cycles. The usage of practical electron-beam irradiation (200 keV; 40 kGy min^-1) with a cost-effective hydroxyl radical scavenger promotes CH₃OH production rate to 0.27 mmol g^-1 min^-1. Moreover, time-resolved experiments with calculations reveal the direct generation of CO₂^•‒ radical anions via aqueous electrons attachment occurred on nanosecond timescale, and cascade hydrogenation steps. Our study highlights a radiolytic route to produce CH₃OH with CO₂ feedstock and introduces a desirable atomic structure to improve performance.