Järi Van den Hoek, from the research group ELCAT, presented his work at the 75^th Annual Meeting conference on the advances in the field of materials science in Montréal, Canada. One of the most promising techniques for Carbon Capture and Utilization (CCU) is the electrochemical reduction of atmospheric or industrial waste CO₂ reduction to a variety of value-added products, including carbon monoxide (CO), formate/formic acid, ethylene (C₂H₄), etc. The production of formate using this sustainable and innovative technology holds significant potential for industrial applications given the high market value and the increasingly stringent regulations on CO₂ emissions. To advance this technology to a technological readiness level (TRL) 5, the combined development of high-performance electrolyzers and active, selective, and stable electrocatalysts is crucial. While electrocatalysts based on Bi, In, and Sn have been proposed for their high catalytic performance, the understanding of their interface properties and their impact on the electrochemical reactor performance remains limited. In this work, we employed two distinct atomic layer deposition (ALD) techniques (Plasma-enhanced (PE) and Thermal (T) ALD) to synthesize low-loading, uniform β-In₂S₃ crystal surface with exceptional performance for formate production and altered triple-phase boundary (TPB). Characterization of the obtained In₂S₃ ALD thin films was conducted using X-ray photoelectron spectroscopy (XPS), grazing-incidence wide angle X-ray scattering (GIWAXS), contact angle (CA) and scanning electron microscope (SEM). The reactive plasma-enhanced deposition allowed for modification of the gas diffusion electrode (GDE) substrate, thereby influencing its hydrophobicity and electrochemical performance through alteration of the TPB. Consequently, the significance of these TPB adaptations was further highlighted for the electroreduction to formate in two diverse electrochemical systems: (i) a small-scale flow-by electrolyzer with a current density exceeding 500 mA cm^-2, selectivity exceeding 90%, and stability of 30 h at 300 mA cm^-2, and (ii) a zero-gap electrolyzer at a current density of 150 mA cm^-2. The high catalytic performance of these uniform In₂S₃ ALD deposited thin films allowed for detailed electrochemical analysis of the reaction pathway and reaction order using a mass-transport coupled Tafel analysis and diluted CO₂ streams, providing clear insights into the electrocatalytic properties and performance of In₂S₃ for formate production. Our results demonstrate that altering the TPB by reducing its hydrophobicity impacts selectivity, activity, and stability but additionally modifies the reaction kinetics, including the limiting current density, exchange density, and the Tafel slope.