In the active interest aroused by electrochemical reactions’ catalysis, related to modern energy challenges, films deposited on electrodes are often preferred to homogeneous catalysts. A particularly promising variety of such films, in terms of efficiency and selectivity, is offered by sprinkling catalytic nanoparticles onto a conductive network. Coupled with the catalytic reaction, the competitive occurrence of various modes of substrate diffusion—diffusion toward nanoparticles (‘nanodiffusion’) against film linear diffusion and solution linear diffusion—is analysed theoretically. It is governed by a dimensionless parameter that contains all the experimental factors, thus allowing one to single out the conditions in which nanodiffusion is the dominant mode of mass transport. These theoretical predictions are illustrated experimentally by proton reduction on a mixture of platinum nanoparticles and carbon dispersed in a Nafion film deposited on a glassy carbon electrode. The density of nanoparticles and the scan rate are used as experimental variables to test the theory.

在与现代能源挑战有关的电化学反应催化引起的积极兴趣中，沉积在电极上的膜通常比均相催化剂更可取。通过将催化纳米颗粒撒在导电网络上，就效率和选择性而言，提供了一种特别有希望的此类薄膜。从理论上分析了与催化反应相结合的各种底物扩散模式（向纳米粒子的扩散（“纳米扩散”）与薄膜线性扩散和溶液线性扩散）的竞争性发生。它是由包含所有实验因素的无量纲参数控制的，因此可以选择纳米扩散是质量传输的主要方式的条件。这些理论预测通过在分散于沉积在玻璃碳电极上的Nafion膜中的铂纳米颗粒和碳的混合物上进行质子还原实验来说明。纳米粒子的密度和扫描速率用作实验变量以检验该理论。