WC and cobalt nanoparticles embedded in nitrogen-doped carbon 3D nanocage derived from H3PW12O40@ZIF-67 for photocatalytic nitrogen fixation

Abstract

Ammonia is a momentous raw chemical in modern life; however, the application of green and environmentally friendly ways to manufacture ammonia remains an enormous dilemma that requests to be conquered at this stage. In this study, we employed H₃PW₁₂O₄₀ (PW₁₂) encapsulated with ZIF-67 as the precursor, and calcinated it at high temperatures in an N₂ atmosphere to synthesize nitrogen-doped graphitic carbon (NGC) nanocages hybrid loaded with WC nanoparticles and Co nanoparticles (WC–Co/NGC). The NH₃ formation rates of WC–Co/NGC-2 with the most palmary photocatalytic effect under visible light and simulated sunlight were 142 μmol g⁻¹ h⁻¹ and 157 μmol g⁻¹ h⁻¹, respectively. The formation rates approach six-fold higher than the individual Co/NGC due to WC–Co/NGC synthesizing after calcination and preserve as a 3D configuration. The specific surface area of WC–Co/NGC-2 far transcends that of Co/NGC, and the pore size distribution manifests many mesoporous structures, which can significantly increase the catalytic process and promote the reaction. Furthermore, the content of pyridine N in WC–Co/NGC-2 is higher than Co/NGC and WC, which can effectively serve as an electron operation center to assist the photocatalytic reaction, reduce the recombination of electrons and holes, and establish an eye-catching catalytic effect. This work not only synthesized WC–Co/NGC with facile tactics but also emerged a brand new speculating orientation for expanding the territory of photocatalytic nitrogen fixation materials.