General heterostructure strategy of photothermal materials for scalable solar-heating hydrogen production without the consumption of artificial energy

Solar-heating catalysis has the potential to realize zero artificial energy consumption, which is restricted by the low ambient solar heating temperatures of photothermal materials. Here, we propose the concept of using heterostructures of black photothermal materials (such as Bi 2 Te 3 ) and infrared insulating materials (Cu) to elevate solar heating temperatures. Consequently, the heterostructure of Bi 2 Te 3 and Cu (Bi 2 Te 3 /Cu) increases the 1 sun-heating temperature of Bi 2 Te 3 from 93 °C to 317 °C by achieving the synergy of 89% solar absorption and 5% infrared radiation. This strategy is applicable for various black photothermal materials to raise the 1 sun-heating temperatures of Ti 2 O 3 , Cu 2 Se, and Cu 2 S to 295 °C, 271 °C, and 248 °C, respectively. The Bi 2 Te 3 /Cu-based device is able to heat CuO x /ZnO/Al 2 O 3 nanosheets to 305 °C under 1 sun irradiation, and this system shows a 1 sun-driven hydrogen production rate of 310 mmol g −1 h −1 from methanol and water, at least 6 times greater than that of all solar-driven systems to date, with 30.1% solar-to-hydrogen efficiency and 20-day operating stability. Furthermore, this system is enlarged to 6 m 2 to generate 23.27 m 3 /day of hydrogen under outdoor sunlight irradiation in the spring, revealing its potential for industrial manufacture. The 1 sun-heating temperatures of photothermal materials can be generally elevated from ~90 °C to ~300 °C by hybridizing with infrared insulating materials, capable of driving methanol reforming to 310 mmol g −1 h −1 over CuO x /ZnO/Al 2 O 3 nanosheets.