Synergistically enhancing CO2 adsorption/activation and electron transfer in ZIF-67/Ti3C2Tx MXene for boosting photocatalytic CO2 reduction

Abstract

To enhance the photocatalytic efficiency of ZIF-67 (Zeolitic Imidazolate Framework-67), we integrated it with Ti3C2Tx MXene through in-situ synthesis and assessed the effects of different MXene concentrations on photocatalytic activity. We identified ZIF-67/Ti3C2Tx MXene as the optimal catalyst (denoted as ZT-450), yielding CO, CH4, and H2 at 62.7, 6.7, and 7.3 μmol g−1, respectively. The CO productive rate achieved by ZT-450 exhibits a substantial enhancement, outperforming both ZIF-67 and Ti3C2Tx by factors of 16.1 and 4.8, respectively. After introducing Ti3C2Tx in ZIF-67, CO2 adsorption ability achieves 127.90 μmol g−1, much higher than those of pure ZIF-67 and Ti3C2Tx. Combining Density Functional Theory (DFT) calculations, we established that introducing Ti3C2Tx in ZIF-67 facilitates rapid electron transfer and improves light absorption, CO2 activation. In-situ DRIFTS measurements of photocatalytic CO2 reduction reaction (CO2RR) on ZIF-67/Ti3C2Tx MXene composite were employed to reveal the emergence of intermediates such as *COOH, *CHO, *OCH3, etc., and elucidate the mechanism accordingly. This research contributes to the advancement of photocatalytic CO2RR, offering insights into applying Ti3C2Tx MXene in photocatalysis.