Electrocatalysis of oxygen evolution reaction (OER), one of the most important members in clean and efficient energy conversion, requires increasing studies on reaction process analysis, catalyst investigation and evaluation and so on through in situ experiments. The bottleneck is the difficulties on clear and precise understanding towards the multi-step reactions with fast reaction rates. Interdigitated array (IDA) electrodes with sensitive responses on the generation, transfer and collection of reaction products are proposed and utilized as a convenient and effective tool to in situ monitor and characterize the reaction thermodynamics and kinetics information. Herein, nickel–iron hydroxide, a promising and novel OER catalyst, is chosen as the candidate to demonstrate the merit of IDA on studying the OER. With the generator-collector mode, the real-time oxygen evolution process is monitored precisely with the IDA collector, distinguished it from the general catalytic current which is normally recorded with conventional electrochemical method. In another word, the actual faradaic efficiency was observed experimentally with IDA electrodes, which is often misled as 100% in many works. The diffusion of the reaction products has been ‘seen’ as well with the generator-collector mode. This general tool (IDA) may make more contributions on the study of reaction process of all electrocatalytical reactions.
Molybdenum disulfide (MoS2) has been deemed as one of the promising noble-metal-free electrocatalysts for hydrogen evolution reaction (HER), but it suffers from the inert basal plane and low electronic conductivity. Regulating the morphology of MoS2 during the synthesis on conductive substrates is a synergistic strategy for enhancing the HER performance. In this work, vertical MoS2 nanosheets were fabricated on carbon cloth using an atmospheric pressure chemical vapor deposition method. The growth process could be effectively tuned through introducing hydrogen gas during vapor deposition process, resulting in nanosheets with increased edge density. The mechanism for edge-enriching through controlling the growth atmosphere is systematically studied. The as-prepared MoS2 exhibits excellent HER activity due to the combination of optimized microstructures and coupling with carbon cloth. Our findings provide new insights to design advanced MoS2-based electrocatalysts for HER. 
The catalytic reactions of photoelectrochemical water splitting attracts tremendous attention as a promising strategy for clean energy production. And the research on reaction mechanism is particularly important in design and developing new catalysts. In this work, the special electrochemical tool of interdigitated array (IDA) electrodes was utilized in investigating the photoelectrochemical oxygen evolution reaction process and detecting the reaction product in situ with the generation-collection mode. TiO2 was taken as a model catalyst and was decorated onto the IDA generator electrode through an electrophoresis method, so that the photoelectrochemical water splitting can take place on the IDA generator and the reaction product can be detected directly with the IDA collector in real time. It is found that TiO2 can be successfully decorated onto the surface of IDA electrode with the expected photoelectrochemical activity, and the generation-collection mode reveals and distinguishes the production of O2 from the overall photoelectrochemical current on TiO2 generator. The mass transfer process of O2 from the TiO2 generator to the collector could be observed as well. Large overall current at high potential range indicates the possible increasing production of the byproducts or nonfaradaic current.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.