Controlling metallic Co0 in ZIF-67-derived N-C/Co composite catalysts for efficient photocatalytic CO2 reduction

Abstract

An efficient photocatalytic CO 2 reduction has been reported in ZIF-67-derived-Co nanoparticles (NPs) encapsulated in nitrogen-doped carbon layers (N-C/Co). This work demonstrates that the pyrolysis temperature is crucial in tuning the grain size and components of metallic Co 0 of N-C/ Co composite catalysts, which optimizes their photocatalytic activities. Syntheses were conducted at 600, 700, and 800°C giving the N-C/Co-600, N-C/Co-700, and N-C/Co-800 samples, respectively. N-C layers can well wrap the Co NPs obtained at a low pyrolysis temperature (600°C) owing to their smaller grains than those of other samples. A high metallic Co 0 content in the N-C/Co-600 sample can be attributed to the effective inhibition of surface oxidation. By contrast, the surface CoO x oxides in the N-C/Co-700 and N-C/Co-800 samples cover inside Co cores, inhibiting charge separation and transfer. As a result, the N-C/Co-600 sample yields the best photocatalytic activity. The carbon monoxide and hydrogen generation rates are as high as 1.62 × 10 4 and 2.01 × 10 4 µmol g −1 h −1 , respectively. Additionally, the Co NPs make composite catalysts magnetic, enabling rapid and facile recovery of catalysts with the assistance of an external magnetic field. This work is expected to provide an instructive guideline for designing metal-organic framework-derived carbon/metal composite catalysts.

Construction of a ternary WO3/CsPbBr3/ZIF-67 heterostructure for enhanced photocatalytic carbon dioxide reduction

“…The Co 2p signal (Fig. 2b) can be deconvoluted into two peaks corresponding to Co 2p 1/2 (796.2 eV) and Co 2p 3/2 (780.2 eV), both of which were in accordance with those previously reported for ZIF-67 [27,28]. For the W 4f spectra (Fig.…”

Fabricating a hollow cuboctahedral structure for N-doped carbon coated p-n heterojunctions towards high-performance photocatalytic organic transformation

“…5 and Fig. S13 the photo-induced electrons from CuO can enrich at the conduction band of NiO, at the meantime, the photo-induced holes from NiO can transfer to the valence band of CuO [32,46]. The Mott-Schottky plot of hollow cuboctahedral CNNCH has shown a volcano-shape curve, further indicating the existence of pn junctions in the sample (Fig.…”

A Review on Removal of Carbon Dioxide (CO2) using Zeolitic Imidazolate Frameworks: Adsorption and Conversion via Catalysis

“…In contrast, there is a high probability of surface oxidation at high carbonization temperature leading to a surface with CoOx oxides that inhibit the charge separation and transfer. Thus, the N-C/Co-600 sample exhibited the best photocatalytic activity [347] .…”