Remarkable gas bubble transport driven by capillary pressure in 3D printing-enabled anisotropic structures for efficient hydrogen evolution electrocatalysts

Additive manufacturing technologies have been proved as a promising method to achieve electrocatalysts with periodic micro-size pores, while the nano-sized interspace of the material structures and their corresponding gas bubbles transfer process are not explored in detail. Herein, we employ the shear force alignment in additive manufacturing to design NiMo-based structures with anisotropic porous channels as electrocatalysts for hydrogen evolution reaction (HER) in seawater. Based on the complementary experimental and theoretical investigation, the unique anisotropic structure not only fully exposes the active sites in the electrolyte, but also facilitates the rapid electrolyte-hydrogen phase conversion during electrochemical reactions. In this case, the obtained 3D electrode exhibits superior electrocatalytic performance and excellent long-term operational stability with an extremely low overpotential of similar to 150 mV at a current density of 500 mA/cm(2) in 1 M KOH seawater. This work will provide a practical scenario for designing highly-efficient HER electrocatalysts.

Automated summary

In this study, shear force alignment in additive manufacturing was used to design NiMo-based structures with anisotropic porous channels as electrocatalysts for hydrogen evolution reaction (HER) in seawater. Both experimental and theoretical investigations were conducted to demonstrate the unique anisotropic structure's ability to fully expose active sites and facilitate rapid electrolyte-hydrogen phase conversion. The obtained 3D electrode showed superior electrocatalytic performance and long-term operational stability in seawater.