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• Monolithic nickel foam catalyst grown in situ. • The temperature rises to 173° solely under visible light. • Synergistic oxidation of lattice oxygen and free radicals. • Detailed toluene photothermal degradation was explored. • Energy-efficient toluene elimination method. Recent research highlights the pressing need for innovative and practical oxidation degradation technologies for volatile organic compounds (VOCs). In this study, a monolithic catalyst was successfully developed by loading Pt-CeO 2 onto nickel foam (NF) matrix through hydrothermal and reduction methods. The photothermal catalytic performance was investigated at room temperature for varying Pt content, toluene concentration, light source type, and water content. Remarkably, the toluene removal efficiency and CO 2 selectivity stabilized at 98.8 % and 74.6 %, respectively, within less than 10 min of light activation. The d-d transition thermal effect of CeO 2 and plasma effect of Pt enhanced light-to-heat conversion and active free radical generation (•O 2 – and •OH) through light absorption, respectively. The NF matrix's excellent thermal conductivity ensured a rapid increase in catalyst temperature upon visible light irradiation, reaching 173 °C. The study demonstrated that both the Mars-van Krevelen (Mvk) oxidation process, driven by temperature increase from near-infrared (NIR) absorption, and the free radical oxidation process, induced by higher energy illumination, synergistically contributed to toluene decomposition and mineralization. The catalyst's morphology, physical and chemical properties, surface synergistic oxidation process involving gaseous oxygen and free radicals, and toluene degradation pathway were thoroughly analyzed. We believe that this coexistence of thermocatalytic and photocatalytic mechanisms in a monolithic catalyst driven by renewable solar energy holds significant potential for practical applications and warrants further exploration. [ABSTRACT FROM AUTHOR]

Photothermal synergistic oxidation of formaldehyde on CeO 2 -rGO-NF catalyst. [Display omitted] • The load of CeO 2 is facilitated by rGO. • Temperature spontaneously heating to 170 °C under light illumination. • The oxidation properties of lattice oxygen are excited. • Photogenerated O 2 – promoted the cycle of lattice oxygen. • Surface reaction mechanism was clarified. Photocatalysis is a feasible method for degrading indoor formaldehyde (HCHO) pollutants. To improve the purification efficiency and lower the cost of using noble metals as the primary component of the catalyst, synergistic catalysis involving two catalytic modes, such as thermocatalysis/photocatalysis, has attracted significant attention. In this study, a monolithic catalyst was prepared by loading reduced graphene oxide (rGO) and cerium dioxide (CeO 2) on a nickel foam (NF) matrix. It was observed that the HCHO removal efficiency could be > 93 % under xenon light. The pre-deposited rGO on the NF matrix served as the photothermal conversion layer and contributed to the uniform and stable loading of CeO 2. The surface temperature of this synthesized monolithic catalyst could rapidly rise to 170 °C. In addition, the heat was distributed evenly because of the increased near-infrared (NIR) light absorption caused by the added rGO and high electron mobility owing to the heat-conducting property of NF. At this temperature, the oxidation of HCHO was stimulated not only by the lattice oxygen of CeO 2 but also by the production of O 2 – via oxidation by photogenerated electrons. In addition, O 2 – would reoxidize Ce3+ to Ce4+ on oxygen vacancies and accelerate the lattice oxygen consumption and supply cycle to reinforce the existing Mars-van Krevelen (MvK) mechanism. [ABSTRACT FROM AUTHOR]