Electrochemical Reduction of CO₂ on Au Electrocatalysts in a Zero‐Gap, Half‐Cell Gas Diffusion Electrode Setup: a Systematic Performance Evaluation and Comparison to an H‐cell Setup**

Based on H-cell measurements, gold (Au) is one of the most selective catalysts for CO 2 reduction reaction (CO RR) to CO. To ensure a high dispersion, typically Au small nanoparticles (NPs) are used as catalyst. However, preparation NPs based conventional synthesis methods often requires use surfactants such polyvinylpyrrolidone (PVP). Here, we present systematic evaluation performance laser-generated, surfactant-free RR in gas diffusion electrode (GDE) setup and compare results investigations an configuration. The GDE supplies continuous stream at electrode−electrolyte interface circumvent mass transport limitations encountered H-cells. We investigate influence catalyst loading effect PVP. Comparing two screening methods, i.e. it shown that same can be substantially different environments. In without liquid electrolyte-catalyst higher rate, but lower faradaic efficiendy determined. Independent setup, presence PVP favours hydrogen evolution (HER), however, more detrimental than H-cell.