Engineering 3D-printed carbon structures with atomic layer deposition coatings as photoelectrocatalysts for water splitting

Abstract

Three-dimensional (3D)-printing has evolved as a popular technique for producing customized parts and devices. 3D conductive structures made of metals or carbon-based materials are highly preferable in the field of electrochemistry. Compared to their metal counterparts, 3D carbon structures printed by the filament extrusion technique are readily available to end users, with the advantages of reduced electrode mass and broad compatibility with harsh environments that might be required for electrochemical applications. To elevate the applicability of 3D carbon electrodes in sensing, catalysis, energy storage, etc., surface or chemical modifications and coating of functional layers are essential. Atomic layer deposition (ALD) is an ideal deposition tool for creating coatings on geometrically complicated structures, yet the surface chemistry of the inert 3D carbon electrodes critically affects the initial growth. We performed a straightforward surface treatment, also known as ‘activation’, to improve the surface wettability and promote the ALD of TiO₂, SiO₂, and Al₂O₃ at low deposition temperatures. We applied the ALD coated electrodes for light-enhanced water splitting hydrogen and oxygen evolution reactions (HER, OER). In addition, we showed that 3D electrodes can be prepared in different geometrical shapes and sizes, as their metal counterparts. This work presents the versatility of ALD coatings on 3D carbon platforms, tunable for many other applications.