High-performance hydrogen evolution electrocatalysis using proton-intercalated TiO2 nanotube arrays as interactive supports for Ir nanoparticles
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Nguyen, Nhat Truong
Manojlović, Dragan D.
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Developing ultraefficient electrocatalytic materials for the hydrogen evolution reaction (HER) with low content of expensive platinum group metals (PGMs) via low-energy-input procedures is the key to the successful commercialization of green water electrolysis technologies for sustainable production of high-purity hydrogen. In this study, we report a facile room-temperature synthesis of ultrafine metallic Ir nanoparticles on conductive, proton-intercalated TiO2 nanotube (H-TNT) arrays via galvanic displacement. A series of experiments demonstrate that a controlled transformation of the H-TNT surface microstructure from neat open-top tubes to disordered nanostripe bundles (“nanograss”) is highly beneficial for providing an abundance of exposed Ir active sites. Consequently, for nanograss-engineered composites, outstanding HER activity metrics are achieved even at very low Ir(III) precursor concentrations. An optimum Ir@TNT cathode loaded with 5.7 μgIr cm−2 exhibits an overpotential of −...63 mV at −100 mA cm−2 and a mass activity of 34 A mgIr−1 at −80 mV under acidic conditions, along with excellent catalytic durability and structural integrity. Density functional theory (DFT) simulations reveal that the hydrogen-rich TiO2 surface not only stabilizes the deposited Ir and weakens its H binding strength to a moderate intensity, but also actively takes part in the HER mechanism by refreshing the Ir catalytic sites near the Ir|H–TiO2 interface, thus substantially promoting H2 generation. The comprehensive characterization combined with theory provides an in-depth understanding of the electrocatalytic behavior of H-TNT supported PGM nanoparticles and demonstrates their high potential as competitive electrocatalyst systems for the HER.
Source:Journal of Materials Chemistry A, 2020, 8, 43, 22773-22790
- Royal Society of Chemistry
- Development, characterization and application nanostructured and composite electrocatalysts and interactive supports for fuel cells and water electrolysis (RS-172054)
- Ministry of Education, Science and Technological Development, Republic of Serbia, Grant no. 451-03-68/2020-14/200053 (University of Belgrade, Institute for Multidisciplinary Research) (RS-200053)
- Ministry of Education, Science and Technological Development, Republic of Serbia, Grant no. 451-03-68/2020-14/200146 (University of Belgrade, Faculty of Physical Chemistry) (RS-200146)
- Bilateral cooperation project between the Republic of Serbia and the Federal Republic of Germany (project years 2020–2021, No. 22), as well as the ERC and DFG.
- The computations and data handling were enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) at National Supercomputer Centre (NSC) at Link¨oping University, partially funded by the Swedish Research Council through grant agreement No. 2018-05973.
- The networking support from COST action MP1407 is greatly appreciated.