Chang, Sih WeiSih WeiChangChen, Yen JenYen JenChenWan, DehuiDehuiWanHSUEN-LI CHEN2023-07-042023-07-042023-01-0120507488https://scholars.lib.ntu.edu.tw/handle/123456789/633368With the rapid growth in global energy consumption, the recovery of waste heat is becoming an important issue. Nevertheless, the recovery of near-room-temperature waste heat remains challenging because the slight temperature difference with the surroundings leads to extremely low thermoelectric power generation. In this study, we combined a daytime radiative cooling (DRC) technology with a thermoelectric generator (TEG) to efficiently recover near-room-temperature waste heat. We investigated the effects of the thermal radiation and thermal conduction properties of DRC materials on near-room-temperature waste heat recovery (WHR). We designed a hierarchical micro-nano h-BN/ZnO composite (MNHZC) that possessed an outstanding daytime radiative cooling ability and moderate thermal conductivity. With this hierarchical h-BN/ZnO composite, we achieved record-high levels of thermoelectric power generation of 225.3 and 412.3 mW m−2 during the daytime and nighttime, respectively, with enhancements in thermoelectric power of 1030 and 190%, respectively. The attractive power generation ability of the MNHZC/TEG system suggests its great potential in low-grade waste heat recovery and environmental energy harvesting by consistently generating power in both the daytime and nighttime.[SDGs]SDG7journal article10.1039/d3ta01436c2-s2.0-85161526249https://api.elsevier.com/content/abstract/scopus_id/85161526249