Ambient sunlight-driven CO 2 methanation cannot be realized due to the temperature being less than 80 °C upon irradiation with dispersed solar energy. In this work, a selective light absorber was used to construct a photothermal system to generate a high temperature (up to 288 °C) under weak solar irradiation (1 kW m −2 ), and this temperature is three times higher than that in traditional photothermal catalysis systems. Moreover, ultrathin amorphous Y 2 O 3 nanosheets with confined single nickel atoms (SA Ni/Y 2 O 3 ) were synthesized, and they exhibited superior CO 2 methanation activity. As a result, 80% CO 2 conversion efficiency and a CH 4 production rate of 7.5 L m −2 h −1 were achieved through SA Ni/Y 2 O 3 under solar irradiation (from 0.52 to 0.7 kW m −2 ) when assisted by a selective light absorber, demonstrating that this system can serve as a platform for directly harnessing dispersed solar energy to convert CO 2 to valuable chemicals.

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 Bi2Te3) and infrared insulating materials (Cu) to elevate solar heating temperatures. Consequently, the heterostructure of Bi2Te3 and Cu (Bi2Te3/Cu) increases the 1 sun-heating temperature of Bi2Te3 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 Ti2O3, Cu2Se, and Cu2S to 295 °C, 271 °C, and 248 °C, respectively. The Bi2Te3/Cu-based device is able to heat CuOx/ZnO/Al2O3 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 m2 to generate 23.27 m3/day of hydrogen under outdoor sunlight irradiation in the spring, revealing its potential for industrial manufacture.

Converting carbon dioxide (CO2) into value-added fuels or chemicals through photothermal catalytic CO2 hydrogenation is a promising approach to alleviate the energy shortage and global warming. Understanding the nanostructured material strategies in the photothermal catalytic CO2 hydrogenation process is vital for designing photothermal devices and catalysts and maximizing the photothermal CO2 hydrogenation performance. In this Perspective, we first describe several essential nanomaterial design concepts to enhance sunlight absorption and utilization in photothermal CO2 hydrogenation. Subsequently, we review the latest progress in photothermal CO2 hydrogenation into C1 (e.g., CO, CH4, and CH3OH) and multicarbon hydrocarbon (C2+) products. Finally, the relevant challenges and opportunities in this exciting research realm are discussed. This perspective provides a comprehensive understanding for the light–heat synergy over nanomaterials and instruction for rational photothermal catalyst design for CO2 utilization.

Cu-based nanocatalysts are the cornerstone of various industrial catalytic processes. Synergistically strengthening the catalytic stability and activity of Cu-based nanocatalysts is an ongoing challenge. Herein, the high-entropy principle is applied to modify the structure of Cu-based nanocatalysts, and a PVP templated method is invented for generally synthesizing six-eleven dissimilar elements as high-entropy two-dimensional (2D) materials. Taking 2D Cu2Zn1Al0.5Ce5Zr0.5Ox as an example, the high-entropy structure not only enhances the sintering resistance from 400 °C to 800 °C but also improves its CO2 hydrogenation activity to a pure CO production rate of 417.2 mmol g−1 h−1 at 500 °C, 4 times higher than that of reported advanced catalysts. When 2D Cu2Zn1Al0.5Ce5Zr0.5Ox are applied to the photothermal CO2 hydrogenation, it exhibits a record photochemical energy conversion efficiency of 36.2%, with a CO generation rate of 248.5 mmol g−1 h−1 and 571 L of CO yield under ambient sunlight irradiation. The high-entropy 2D materials provide a new route to simultaneously achieve catalytic stability and activity, greatly expanding the application boundaries of photothermal catalysis.

Fe3Si aerogel is a new photothermal material with full absorption of sunlight, excellent anti-corrosion resistance and 2–3 nm sized pores, showing high solar-thermal efficiency of 91.8% and remarkable water evaporation rate of 2.08 kg m−2 h−1 in seawater, and 1 kg m−2 h−1 in strong corrosive solutions under one sunlight irradiation.