Multilevel Hollow MXene Tailored Low-Pt Catalyst for Efficient Hydrogen Evolution in Full-pH Range and Seawater

Multilevel hollow structures provide a superior material platform to conventional designs for exceptional functionalities enabled by wide tailorability of interfacial properties and local microenvironments. Herein, a facile strategy is reported for tailoring the electrocatalytic performance of a low-Pt catalyst over a wide range of pH conditions using multilevel hollow MXene with sufficient diffusion channels, multiple reactive surface areas, and robust frameworks with high conductivity and hydrophilic and aggregation resistance. Their synergy with ultrafine Pt creates efficient multifunctional catalytic interfaces with high Pt utilization, and overall enhanced charge transport, H+/water adsorption activation, intermediate H binding, and ionic/mass exchange. The resultant catalyst fully exceeds the commercial 20% Pt/C by 10-20 folds in mass activity for hydrogen evolution through the full pH range. The highest mass activity of 12.94 A mg(Pt)(-1) is achieved in an alkaline electrolyte with 1/8 Pt usage of 20% Pt/C. This catalyst also exhibits the best combination of high activity, long lifetime (250 h, 31 times of Pt/C), and nearly 100% Faradaic efficiency among 20% Pt/C (8 h) and documented electrocatalysts (10-100 h) for hydrogen production in natural seawater. This study offers an effective interface-engineering strategy to regulate electrocatalysis over broad chemical conditions to meet the complicated application criteria.