Platinum single-atom and cluster catalysis of the hydrogen evolution reaction

Abstract

Platinum-based catalysts have been considered the most effective electrocatalysts for the hydrogen evolution reaction in water splitting. However, platinum utilization in these electrocatalysts is extremely low, as the active sites are only located on the surface of the catalyst particles. Downsizing catalyst nanoparticles to single atoms is highly desirable to maximize their efficiency by utilizing nearly all platinum atoms. Here we report on a practical synthesis method to produce isolated single platinum atoms and clusters using the atomic layer deposition technique. The single platinum atom catalysts are investigated for the hydrogen evolution reaction, where they exhibit significantly enhanced catalytic activity (up to 37 times) and high stability in comparison with the state-of-the-art commercial platinum/carbon catalysts. The X-ray absorption fine structure and density functional theory analyses indicate that the partially unoccupied density of states of the platinum atoms' 5d orbitals on the nitrogen-doped graphene are responsible for the excellent performance. S ecuring renewable and reliable sources of clean energy is one of the world's foremost challenges. Addressing this challenge is not only critical for the global economy but will also aid in the mitigation of environmental and health hazards caused by fossil fuels 1 . Hydrogen is the cleanest fuel available and is believed to be one of the most promising energy sources of the twenty-first century 2,3 . However, the majority of the hydrogen produced today is derived from steam-reformed methane, which is sourced from fossil reserves and produces a substantial amount of CO 2 (ref. 4). The production of hydrogen from water electrolysis is a promising alternative to the current CO 2 -emitting fossil fuel-based energy systems 5,6 .Platinum (Pt)-based catalysts are generally considered to be the most effective electrocatalysts for the hydrogen evolution reaction (HER) 5,7 . Unfortunately, Pt is expensive and scarce, limiting the commercial potential for such catalysts. The development of active, stable and inexpensive electrocatalysts for water splitting is a key step in the realization of a hydrogen economy, which is based on the use of molecular hydrogen for energy storage.Significant effort has been devoted to the search of non-preciousmetal-based HER catalysts, including sulfide-based materials 8-11 , and C 3 N 4 (refs 12-14). Although these candidate materials show promising activities for the HER, the activities of these catalysts in their present form are insufficient for industrial applications 15 .To overcome the challenges associated with the Pt HER catalysts and to drive the cost of H 2 production from water electrolysis down, it is very important to markedly decrease the Pt loading and increase the Pt utilization efficiency. Currently, supported Pt nanoparticles (NPs) are typically used to promote Pt activity towards the HER. Unfortunately, the geometry of the NPs limit the majority of the Pt atoms to the particle core, deeming them ineffect...

Electrocatalysts for Hydrogen Evolution in Alkaline Electrolytes: Mechanisms, Challenges, and Prospective Solutions

“…Sun and co‐workers have compared the atomically small particle of Pt or their clusters with commercial Pt/C 66. They concluded that reduction in size can enhance the Pt activity up to 37 times than commercial Pt/C because of highly exposed surface and involvement of entire active material in catalytic reaction.…”

Oxide-based nanomaterials for fuel cell catalysis: the interplay between supported single Pt atoms and particles

“…In particular, anchoring of noble metal atoms at appropriate supports requires the presence of specific adsorption sites that are capable of stabilizing metal atoms against sintering and agglomeration into particles. Such sites have been identified on the surfaces of graphene, [11][12][13] nitrides, [14][15][16][17][18] zeolites, 19 and metal oxides. [20][21][22][23][24][25][26][27][28][29][30][31] In most cases, atomically dispersed metals are found to be anchored in surface cationic positions of the host oxide.…”

Potential‐Cycling Synthesis of Single Platinum Atoms for Efficient Hydrogen Evolution in Neutral Media

“…Then, by normalizing activities to the Pt loadings and deducting the contributions of the NTs and NFs (see the Experimental Section for details), the HER mass activities of Pt/C and single Pt atoms on PtSA‐NT‐NF were given to be 17 and 70 Ag −1 , respectively, at η =50 mV (this overpotential was chosen by following Ref. 12b). The value for single Pt atoms on PtSA‐NT‐NF is four times that of Pt/C, indicating the more efficient HER performance of the single Pt atoms.…”