Mitigating bubble shielding in electrocatalytic water splitting: A review on the design of superhydrophilic/underwater superaerophobic self-supported electrocatalysts

Electrocatalytic overall water splitting for hydrogen production is regarded as an up-and-coming technology with significant potential to replace fossil fuels. The performance of electrocatalysts directly dictates the efficiency of hydrogen generation. Although researchers have developed various strategies to enhance their performance, the practical outcomes often remain suboptimal. This is primarily due to the excessive adhesion of gas bubbles on the electrode surface during the electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). This bubble adhesion blocks active sites, impedes mass transport, and consequently diminishes the overall gas evolution efficiency. To address this challenge, constructing wetting surfaces with superhydrophilic and underwater superaerophobic can effectively mitigate bubble adhesion. This review provides a systematic exploration of strategies for constructing superhydrophilic/underwater superaerophobic self-supported electrocatalysts to mitigate bubble shielding effects and enhance gas evolution reaction efficiency. This review highlights recent advances in growing transition metal sulfides, phosphides, and nitrides on three-dimensional substrates (e.g., nickel foam), achieving exceptional electrocatalytic performance through structural design and chemical modification. Furthermore, we propose a design principle centered on interface-structure synergy, offering new perspectives for developing high-performance non-precious metal electrocatalysts, while also discussing future prospects and challenges.