Accelerated electro-photocatalytic and phytotoxicity applications of synthesized hybrid molecules enhanced MoO2@Nickel cobaltate nanocomposite

Abstract

The commercial RuO₂ used for electrochemical oxygen evolution reaction (OER) is more expensive. Also nickel foam and glassy carbon substrates were very expensive for the fabrication of working electrodes that ignore/minimize the practical applications. Hence we used low-cost and most abundant elements for the fabrication of working electrode with graphite substrate effectively. Likewise, there is no photocatalytic study available on various pollutants by the same materials leads to limit the photocatalytic application in real-time wastewater treatment. In this study, simple synthesis of reduced graphene oxide (rGO), poly-1-aminoanthraquinone (PAAQ), and layered double hydroxide (LDH) supported MoO₂–NiCo₂O₄ photo-electrocatalytic materials by the hydrothermal process has done and extensively investigated for physicochemical properties. The optical band gap energy of rGO@MoO₂/NiCo₂O₄ NCs (RMNCO) was found to be 2.33 eV, which implies that it has higher electrical conductivity comparatively. As a BET result, the highest surface area observed for RMNCO composite due to the strong interaction between the interlayer structure of rGO and MoO₂/NiCo₂O₄ particles, it indicates the well binding and lowest interparticle distance. The better OER performance has observed in RMNCO due to high surface area accomplished and also low Tafel slope with overpotential values of 71 mV dec⁻¹ and 327 mV respectively. The photocatalytic degradation study was conducted against Methylene blue (MB), Rhodamine B (RhB) and Acetaminophen (AP) drug under various parameters respectively. The highest degradation efficiency was calculated to be 91.30, 97.37 and 95.62% and it obeyed the pseudo-first-order kinetic model. Also, the antibacterial activity was investigated against gram-positive, gram-negative bacteria and the results showed the highest significant activity. In addition to that, degraded dye solution was utilized to conduct phytotoxicity study to grow mung bean for examining the effects on toxicity. The entire results showed that synthesized photo/electrocatalysts are outstanding candidates for OER, photocatalytic remediation and antibacterial applications etc.