On the Controlled Loading of Single Platinum Atoms as a Co‐Catalyst on TiO₂ Anatase for Optimized Photocatalytic H₂ Generation

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.201908505.Single-atom (SA) catalysis is a novel frontline in the catalysis field due to the often drastically enhanced specific activity and selectivity of many catalytic reactions. Here, an atomic-scale defect engineering approach to form and control traps for platinum SA sites as co-catalyst for photocatalytic H 2 generation is described. Thin sputtered TiO 2 layers are used as a model photocatalyst, and compared to the more frequently used (001) anatase sheets. To form stable SA platinum, the TiO 2 layers are reduced in Ar/H 2 under different conditions (leading to different but defined Ti 3+ -O v surface defects), followed by immersion in a dilute hexachloroplatinic acid solution. HAADF-STEM results show that only on the thin-film substrate can the density of SA sites be successfully controlled by the degree of reduction by annealing. An optimized SA-Pt decoration can enhance the normalized photocatalytic activity of a TiO 2 sputtered sample by 150 times in comparison to a conventional platinum-nanoparticle-decorated TiO 2 surface. HAADF-STEM, XPS, and EPR investigation jointly confirm the atomic nature of the decorated Pt on TiO 2 . Importantly, the density of the relevant surface exposed defect centers-thus the density of Pt-SA sites, which play the key role in photocatalytic activity-can be precisely optimized.Single-atom (SA) or single-site catalysis (SACs) has over the past years become an increasingly fascinating topic in the catalysis field. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] SACs have allowed new approaches in heterogeneous catalysis, [12,13] minimized the use of precious metals, [14]

Recent Progress in Single‐Atom Catalysts for Photocatalytic Water Splitting

“…By means of an atomic-level defect engineering technique, Schmuki and coworkers used single Pt atoms to decorate the TiO 2 thin layer, which were highly active and stable for H 2 evolution under photocatalysis. [117] It was revealed that the H 2 evolution rate on atomic Pt sites was enhanced, which was 150 times higher than that on Pt NPs. In addition, atomic Pt Figure 7.…”

“…[116] Similarly, another single-atom system has been established for photocatalytic hydrogen evolution, in which atomically dispersed Pt was embedded into the oxygen vacancies of TiO 2 . [98,117] In carbon-based SACs, C vacancies can offer abundant defect sites to anchor various metal atoms via strong interactions. [34] Wei et al reported that isolated Pt atoms can be stably anchored on the C vacancies/edges of mesoporous carbon, which can effectively avoid aggregation of Pt atoms (Figure 5b).…”

Effect of size and crystalline phase of TiO2 nanotubes on cell behaviors: A high throughput study using gradient TiO2 nanotubes

“…Over the past decade, self-aligned TiO 2 nanotubes (TNTs) grown on titanium have been extensively developed in environmental protection, photocatalysis [ [6] , [7] , [8] ], sensors [ 9 , 10 ], dye-sensitized solar cells [ 11 , 12 ], and biomedical applications [ [13] , [14] , [15] ] owing to their superior high-specific surface area, specific ion intercalation properties, photocatalysis property, and cost-effective synthesis. In particular, the terrific biocompatibility, corrosion resistance and size controllable properties of TNTs make them promising for biomedical applications, such as orthopedic/dental implants [ 16 , 17 ], blood contact materials [ 18 ], anti-microbial application [ 19 , 20 ], and drug delivery [ 21 , 22 ].…”

Influence of Solvents' Polarity on the Physicochemical Properties and Photocatalytic Activity of Titania Synthesized Using Deinbollia pinnata Leaves

“…Dyes are major coloring agents used in industries for precious stones, paper, leather, plastic, textile, and food production. Hazardous waste water from dyeing process act as a major contaminant to the environment (Murugan and Parimelazhagan, 2014;Hejazi et al, 2020). The dye effluents are usually non-biodegradable, highly oxidizing, and stable to heat and light (Khataee and Mirzajani, 2010; which attributed to their toxicity, undesirable aesthetic, and carcinogenicity (Khalik et al, 2017).…”