The development of efficient and stable photocatalysts to solve environmental issues is essential and remains a big challenge. In this work, flower-like CoNiFe-LDH is deposited in situ on g-C3N4 nanosheets, successfully constructing a Z-scheme heterojunction CoNiFe-LDH/g-C3N4 photocatalyst for the photoreduction of CO2 and photodegradation of MB dye. The synthesized nanohybrid shows superior photocatalytic CO2 performance (42.04 μmol g−1 h−1) and fast photodegradation MB performance (0.1057 min−1). The improved photocatalytic performance was attributed to the formation of the Z-scheme heterojunction with matched energy bands, and the intimate heterojunction contact interface, which significantly enhanced the interfacial charge transfer rate and improved the separation efficiency of electron–hole pairs. Moreover, the photocatalytic mechanism was proposed based on PL, photocurrent responses, EIS, and EPR experiments. This work can shed light on further application for environmental problems of Z-scheme heterojunction photocatalysts.
Saiya Guo,Huihui Li,Manman Shi,Qianqian Zhu,Jieding Wei,Qingqing Zha,Yonghong Ni
Layered double hydroxides (LDH) have attracted great research interest as catalysts for electrochemical water splitting. However, further enhancing the electrocatalytic activity of LDH materials is still a huge challenge. Here, we designed a mild wet chemical route to successfully prepare conductive metal-organic frameworks (cMOFs) modified hollow CoNiFe-LDH nanocages.Firstly, ZIF-67 nanocubes were etched by Ni 2+ and Fe 3+ ions in turn to form hollow CoNiFe-LDH nanocages. Then, hollow CoNiFe-LDH nanocages reacted with 2,3,6,7,10,11hexahydroxytriphenylene (HHTP) to obtain cMOFs modified hollow CoNiFe-LDH nanocages (labeled as CoNiFe-HHTP). Electrochemical measurements showed that the as-obtained CoNiFe-HHTP exhibited excellent electrocatalytic oxygen evolution reaction (OER) performances. In 1 M KOH solution, the as-obtained CoNiFe-HHTP merely required 209 mV overpotential to deliver a current density of 10 mA cm -2 , with a low Tafel slope of 36.81 mV dec -1 . Also, the as-obtained CoNiFe-HHTP could stably run more than 240 h at a current density of 10 mA cm -2 , exhibiting superb long-term stability. The present work provides a promising strategy to promote the electrocatalytic activity of cheap transition metal LDH materials for electrochemical water decomposition.
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