CC BY-NC 4.0Küspert, SvenSvenKüspertCampbell, Ian E.Ian E.CampbellZeng, ZhiqiangZhiqiangZengBalaghi, S. EsmaelS. EsmaelBalaghiOrtlieb, NiklasNiklasOrtliebThomann, RalfRalfThomannKnäbbeler-Buß, MarkusMarkusKnäbbeler-BußAllen, Christopher S.Christopher S.AllenMohney, Suzanne E.Suzanne E.MohneyFischer, AnnaAnnaFischer2024-07-252024-07-252024Note-ID: 00008EF6https://publica.fraunhofer.de/handle/publica/472076https://doi.org/10.24406/publica-346010.1002/smll.20231126010.24406/publica-3460Vapor-based deposition techniques are emerging approaches for the design of carbon-supported metal powder electrocatalysts with tailored catalyst entities, sizes, and dispersions. Herein, a pulsed CVD (Pt-pCVD) approach is employed to deposit different Pt entities on mesoporous N-doped carbon (MPNC) nanospheres to design high-performance hydrogen evolution reaction (HER) electrocatalysts. The influence of consecutive precursor pulse number (50-250) and deposition temperature (225-300 °C) are investigated. The Pt-pCVD process results in highly dispersed ultrasmall Pt clusters (≈1 nm in size) and Pt single atoms, while under certain conditions few larger Pt nanoparticles are formed. The best MPNC-Pt-pCVD electrocatalyst prepared in this work (250 pulses, 250 °C) reveals a Pt HER mass activity of 22.2 ± 1.2 A mg-1Pt at -50 mV versus the reversible hydrogen electrode (RHE), thereby outperforming a commercially available Pt/C electrocatalyst by 40% as a result of the increased Pt utilization. Remarkably, after optimization of the Pt electrode loading, an ultrahigh Pt mass activity of 56 ± 2 A mg-1Pt at -50 mV versus RHE is found, which is among the highest Pt mass activities of Pt single atom and cluster-based electrocatalysts reported so far.enCO strippinghydrogen evolution reactionmesoporous N-doped carbonsPt clusters and single atomspulsed chemical vapor depositionjournal article