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Passive cooling technologies being free from additional energy consumption, offer significant advantages in reducing carbon emissions and mitigating global warming. However, radiative cooling has a thermodynamic limit, and evaporative cooling requires additional components, which restricts their large‐scale application, respectively. Herein, a radiative/evaporative bifunctional cooling bilayer is presented, featuring an upper layer composed of poly(vinylidene fluoride‐cohexafluoropropene) [P(VdF‐HFP)] integrated with a hygroscopic hydrogel lower layer [polyacrylamide (PAAm)/alginate‐CaCl2]. High solar reflectance (0.916) and long‐wave infrared emittance (0.900) of the P(VdF‐HFP) combined with hydrogel evaporation enable a notable 15.4 °C temperature drop under 706.3 W·m−2 solar radiation. The bilayer is demonstrated to be effective under outdoor conditions for continuous three cloudy days, achieving an average temperature reduction ranging from 6.3 to 15.7 °C. Considering the low cost and simplicity of the preparation method, ease of large‐scale fabrication, and good cooling performance, this bilayer structure provides a promising strategy for the application of passive cooling. [ABSTRACT FROM AUTHOR]

Electrolysis efficiency is significantly hindered by the bubbles on the electrode surface. Therefore, understanding the bubble evolution process is vital to achieve faster detachment at smaller radii. This study experimentally investigates the impact of surface tension and cathodic potential on hydrogen bubble evolution. The findings indicate that adding a small amount (1 × 10−7 M) of anionic surfactant to the acidic solution (1 M H 2 SO 4) results in a 10% reduction in the bubble detachment radius and a substantial decrease in the bubble growth time by approximately 89%. Additionally, further increasing the surfactant concentration has minimal effect on the growth time but continues to lead to the detachment radius decrease which is assumed to be due to the decreased Marangoni force. This study also identifies three distinct bubble growth modes at different surfactant concentrations, linked to varying levels of surfactant adsorption. Furthermore, a force balance model has been developed to describe the bubble growth process. The study concludes that the solutal Marangoni force decreases while electrostatic repulsion increases with rising surfactant concentration. A reduced solutal Marangoni force and increased electrostatic repulsion – are likely the key factors contributing to the accelerated bubble detachment. • Rapid detachment of H 2 bubbles is found at low surfactant concentrations. • Three hydrogen bubble evolution patterns are observed. • Precisely adjusting the Marangoni force. • A force balance model is established for predicting bubble detachment size. [ABSTRACT FROM AUTHOR]