Unravelling platinum nanoclusters as active sites to lower the catalyst loading for formaldehyde oxidation

• Published in: Communications chemistry Vol. 2; no. 1
• Main Authors: Sun, Xiucheng, Lin, Jian, Chen, Yang, Wang, Yuehan, Li, Lin, Miao, Shu, Pan, Xiaoli, Wang, Xiaodong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.03.2019; Nature Publishing Group
• Subjects: 639/638/169/896; 639/638/77/887; 639/925/357/354; Aldehydes; Aluminum oxide; Catalysis; Catalysts; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Decomposition reactions; Formaldehyde; Formates; Nanoclusters; Nanoparticles; Noble metals; Oxidation; Platinum; Titanium dioxide; Volcanoes
• ISSN: 2399-3669; 2399-3669
• DOI: 10.1038/s42004-019-0129-0

Minimizing the use of precious metal remains a challenge in heterogeneous catalysis, such as platinum-based catalysts for formaldehyde oxidation. Here we report the  catalyst system Pt/TiO 2  with low platinum loading of 0.08 wt%, orders of magnitude lower than conventional catalysts. A volcano-like relationship is identified between reaction rates of formaldehyde and platinum sizes in a scale of single-atoms, nanoclusters and nanoparticles, respectively. Various characterization techniques demonstrate that platinum nanoclusters facilitate more activation of O 2 and easier adsorption of HCHO as formates. The activated O facilitates the decomposition of formates to CO 2 via a lower reaction barrier. Consequently, this size platinum with such low loading realizes complete elimination of formaldehyde at ambient conditions, outperforming single-atoms and nanoparticles. Moreover, the platinum nanoclusters exhibit a good versatility regardless of supporting on “active” FeO x or “inert” Al 2 O 3 for formaldehyde removal. The identification of the most active species has broad implications to design cost-effective metal catalysts with relatively lower loadings. It is important to identify heterogeneous catalyst compositions which minimize use of precious metals. Here the authors analyse the size-activity behaviour of platinum-based formaldehyde oxidation catalysts, identifying a volcano relationship with nanometer scale nanoclusters being the most effective.