Engineering efficient carrier transport in TiO2/Ag2.3Se hybrids through synergistic photo-thermoelectric catalyst effect

A photothermoelectric micro-engine is designed via TiO 2 /Ag 2.3 Se heterojunction. • Seebeck-induced electromotive force recovers waste heat for charge separation. • Multi-field coupling generates a 2.3 mV potential, yielding a 1 + 1 > 2 synergy. • FEM models and in-situ Raman confirm autonomous thermodynamic charge pumping. • The self-powered micro-engine achieves 93% efficiency for water remediation. The development of multi-field synergistic catalysis has emerged as a critical frontier for maximizing energy utilization. However, performance of multi-field systems is often bottlenecked by inefficient charge-carrier migration arising from complex field coupling. Herein, we report a high-performance n-type TiO 2 /Ag 2.3 Se photothermoelectric (PTE) catalyst designed to overcome these transport limitations. By integrating thermoelectric functionality into the photocatalytic framework, we establish a 40°C temperature-gradient that triggers a robust Seebeck-driven internal electric field. This PTE coupling yields a photovoltage of 2.3 mV, significantly exceeding the linear summation of individual thermal (1.4 mV) and photo (0.3 mV) contributions. In-situ Raman spectroscopy and finite element method simulations reveal that the synergistic photothermal interaction induces a highly directional flux of charge carriers, effectively suppressing recombination and accelerating interfacial kinetics. Remarkably, the TiO 2 /Ag 2.3 Se composite achieves a photocatalytic degradation efficiency of 93%, far surpassing the combined totals of discrete photocatalysis (41%) and thermoelectric catalysis (13%). This pronounced “1 + 1 > 2” synergy demonstrates a paradigm shift in catalyst design, where wasted thermal energy is converted into a functional driving force for charge separation. This work not only provides deep mechanistic insights into thermal-induced interfacial charge transfer but also establishes a strategic framework for engineering waste-heat-driven micro-engines for self-powered environmental sustainability. Download: Download high-res image (140KB) Download: Download full-size image Thermoelectric modulation in a TiO 2 /Ag 2.3 Se heterostructure converts thermal dissipation into an electromotive force, driving highly efficient solar-to-chemical energy conversion.