The influence of the drop-casted nickel boride catalyst loading on glassy carbon electrodes was investigated in a spectroelectrochemical ATR-FTIR thin-film flow cell applied in alkaline glycerol electrooxidation. The continuously operated radial flow cell consisted of a borehole electrode positioned 50 µm above an internal reflection element enabling operando FTIR spectroscopy. It is identified as a suitable tool for facile and reproducible screening of electrocatalysts under well-defined conditions, additionally providing access to the selectivities in complex reaction networks such as glycerol oxidation. The fast product identification by ATR-IR spectroscopy was validated by the more time-consuming quantitative HPLC analysis of the pumped electrolyte. High degrees of glycerol conversion were achieved under the applied laminar flow conditions using 0.1 M glycerol and 1 M KOH in water and a flow rate of 5 µL min⁻¹. Conversion and selectivity were found to depend on the catalyst loading, which determined the catalyst layer thickness and roughness. The highest loading of 210 µg cm⁻² resulted in 73% conversion and a higher formate selectivity of almost 80%, which is ascribed to longer residence times in rougher films favoring readsorption and C–C bond scission. The lowest loading of 13 µg cm⁻² was sufficient to reach 63% conversion, a lower formate selectivity of 60%, and, correspondingly, higher selectivities of C₂ species such as glycolate amounting to 8%. Thus, only low catalyst loadings resulting in very thin films in the few μm thickness range are suitable for reliable catalyst screening.

在碱性甘油电氧化中应用的光谱电化学 ATR-FTIR 薄膜流通池中研究了滴铸硼化镍催化剂负载对玻碳电极的影响。连续运行的径向流通池由位于内部反射元件上方 50 µm 的钻孔电极组成，可实现操作 FTIR 光谱。它被认为是在明确定义的条件下轻松和可重复筛选电催化剂的合适工具，此外还提供了在复杂反应网络（如甘油氧化）中获得选择性的途径。ATR-IR 光谱对产品的快速鉴定通过对泵送电解液进行更耗时的定量 HPLC 分析进行了验证。^-1。发现转化率和选择性取决于催化剂负载，这决定了催化剂层的厚度和粗糙度。210 µg cm ^-2的最高负载导致 73% 的转化率和几乎 80% 的更高甲酸盐选择性，这归因于在更粗糙的薄膜中更长的停留时间有利于再吸附和 C-C 键断裂。13 µg cm ^-2的最低负载量足以达到63% 的转化率、60% 的较低甲酸盐选择性，以及相应地，C ₂物质（例如乙醇酸盐）的更高选择性达到8%。因此，只有导致几微米厚度范围内非常薄的薄膜的低催化剂负载量才适合可靠的催化剂筛选。