(111c) Pt Single-Atom Catalyst with Precise Structure and High Pt Loading for Enhanced H2 Production

With high H₂ gravimetric density and being relatively inexpensive, methanol is a promising H₂ carrier since it can be manufactured from a variety of sources [1]. Previous study suggested that Pt/CeO₂ single-atom catalysts (SACs) are promising for H₂ production from methanol decomposition [2]. However, their H₂ production efficiency was limited due to significant challenges in the precise control of the local structure and the increase of density of single Pt atoms.

In this work, Pt single atoms with different Pt local coordination structures were clearly present within 1.0Pt/CeO₂ catalysts (i.e., Pt loading = 1.0 wt.%) prepared from different CeO₂ supports (1.0Pt/CeO₂ vs. 1.0Pt/CeO₂-e, e represents Pt single atom embedded in CeO₂ surface lattice). 1.0Pt/CeO₂-e showed much higher activity than 1.0Pt/CeO₂, with the methanol conversion at 250 ^oC on 1.0Pt/CeO₂-e twice of that on 1.0Pt/CeO₂. In addition, 1.0Pt/CeO₂-e demonstrated superior catalytic stability when compared to 1.0Pt/CeO₂. There was no discernible activity loss observed on the former catalyst, whereas deactivation was evident on the latter one. The catalytic activity can be further enhanced by increasing the density of Pt₁ in Pt₁/CeO₂-e. At the Pt loading of 5 wt.%, noticeable Pt clusters were observed on 5.0Pt/CeO₂, whereas exclusive Pt₁ were still present on 5.0Pt/CeO₂-e, even when the Pt loading was increased to 15 wt.%. By using the optimal CeO₂ support, high-density Pt/CeO₂ SACs with Pt loading up to 15 wt.% can be successfully fabricated. It was revealed that the H₂ desorption was the rate-determining step in methanol decomposition. The Pt single-atom site, where Pt was embedded within the CeO₂ surface lattice, facilitated the H₂ desorption, leading to superior catalytic activity in methanol decomposition.

References:

[1] X.Y. Xu, et al., Appl. Catal. B: Environ., 2023, 334, 122839.

[2] L.N. Chen, et al., J. Am. Chem. Soc., 2019, 141, 17995.

With high H₂ gravimetric density and being relatively inexpensive, methanol is a promising H₂ carrier since it can be manufactured from a variety of sources [1]. Previous study suggested that Pt/CeO₂ single-atom catalysts (SACs) are promising for H₂ production from methanol decomposition [2]. However, their H₂ production efficiency was limited due to significant challenges in the precise control of the local structure and the increase of density of single Pt atoms.

In this work, Pt single atoms with different Pt local coordination structures were clearly present within 1.0Pt/CeO₂ catalysts (i.e., Pt loading = 1.0 wt.%) prepared from different CeO₂ supports (1.0Pt/CeO₂ vs. 1.0Pt/CeO₂-e, e represents Pt single atom embedded in CeO₂ surface lattice). 1.0Pt/CeO₂-e showed much higher activity than 1.0Pt/CeO₂, with the methanol conversion at 250 ^oC on 1.0Pt/CeO₂-e twice of that on 1.0Pt/CeO₂. In addition, 1.0Pt/CeO₂-e demonstrated superior catalytic stability when compared to 1.0Pt/CeO₂. There was no discernible activity loss observed on the former catalyst, whereas deactivation was evident on the latter one. The catalytic activity can be further enhanced by increasing the density of Pt₁ in Pt₁/CeO₂-e. At the Pt loading of 5 wt.%, noticeable Pt clusters were observed on 5.0Pt/CeO₂, whereas exclusive Pt₁ were still present on 5.0Pt/CeO₂-e, even when the Pt loading was increased to 15 wt.%. By using the optimal CeO₂ support, high-density Pt/CeO₂ SACs with Pt loading up to 15 wt.% can be successfully fabricated. It was revealed that the H₂ desorption was the rate-determining step in methanol decomposition. The Pt single-atom site, where Pt was embedded within the CeO₂ surface lattice, facilitated the H₂ desorption, leading to superior catalytic activity in methanol decomposition.

References:

[1] X.Y. Xu, et al., Appl. Catal. B: Environ., 2023, 334, 122839.

[2] L.N. Chen, et al., J. Am. Chem. Soc., 2019, 141, 17995.