Controlling hot electron flux and catalytic selectivity with nanoscale metal-oxide interfaces

Abstract

Interaction between metal and oxides is an important molecular-level factor that influences the selectivity of a desirable reaction. Therefore, designing a heterogeneous catalyst where metal-oxide interfaces are well-formed is important for understanding selectivity and surface electronic excitation at the interface. Here, we utilized a nanoscale catalytic Schottky diode from Pt nanowire arrays on TiO2 that forms a nanoscale Pt-TiO2 interface to determine the influence of the metal-oxide interface on catalytic selectivity, thereby affecting hot electron excitation; this demonstrated the real-time detection of hot electron flow generated under an exothermic methanol oxidation reaction. The selectivity to methyl formate and hot electron generation was obtained on nanoscale Pt nanowires/TiO2, which exhibited ~2 times higher partial oxidation selectivity and ~3 times higher chemicurrent yield compared to a diode based on Pt film. By utilizing various Pt/TiO2 nanostructures, we found that the ratio of interface to metal sites significantly affects the selectivity, thereby enhancing chemicurrent yield in methanol oxidation. Density function theory (DFT) calculations show that formation of the Pt-TiO2 interface showed that selectivity to methyl formate formation was much larger in Pt nanowire arrays than in Pt films because of the different reaction mechanism.

Operando Surface Studies on Metal-Oxide Interfaces of Bimetal and Mixed Catalysts

“…With an integrated batch reactor, the evolved chemicurrent and catalytic conversion rate of reactant molecules are monitored simultaneously under the reaction environment. Therefore, the generation of hot electrons is definitely observed in the manner of dramatically increasing chemicurrent, when a full oxidation of methanol (MeOH) occurs at above 40 °C, as shown in Figure e . It is evident that the chemicurrent yield in MeOH oxidation is influenced by dynamics of the hot electron relaxation at the metal-oxide interface.…”

“…(e) Schematic illustration of Pt nanowires/TiO 2 nanodiode and measured current density plots at the elevated reaction temperature under the methanol oxidation reaction. Reproduced under the terms of the CC-BY Creative Commons Attribution 4.0 International license () from ref . Copyright 2021, The Authors, published by Springer Nature.…”

“…Therefore, the generation of hot electrons is definitely observed in the manner of dramatically increasing chemicurrent, when a full oxidation of methanol (MeOH) occurs at above 40 °C, as shown in Figure 3e. 118 It is evident that the chemicurrent yield in MeOH oxidation is influenced by dynamics of the hot electron relaxation at the metal-oxide interface. This "catalytronics" strategy 119 can be widely utilized in future researches on nanotechnology and engineering by controlling the redox process involved in industrial catalytic reactions.…”

Tensile Strain in Tin Oxide Clusters Stabilized by C3N4 for Highly Efficient Visible Light-Driven H2O2 Production

“…Owing to the high surface to volume ratio, adjustable size and structure, rich surface chemistry, and adjustable visible light absorption, the nanoscale metal oxide clusters have emerged as promising cophotocatalysts in the photocatalytic field, which has greatly boosted the advancement of many photocatalytic applications, such as water splitting, nitrogen fixation, organic pollutants degradation, and organic synthesis. − Compared to the corresponding nanoparticles, the cluster structure has fascinating photocatalytic activity due to the inherent structure and enhanced quantum size effect. − Herein, we prepared tin oxide (SnO 2 ) clusters modified g-C 3 N 4 (SnO 2 @g-C 3 N 4 ) for a high-efficient photocatalytic hydrogen peroxide generation reaction. The SnO 2 @g-C 3 N 4 is obtained by introducing acetic acid tin (C 8 H 12 O 8 Sn) in the calcination process of urea.…”

Carboxylated Graphene Nanoribbons for Highly-Selective Ammonia Gas Sensors: Ab Initio Study

“…Using the DFT method, from the standpoint of the energy approach, it was explained why the sensory response of MPcF 4 films to ammonia is noticeably higher than that of MPc films. The use of various approximations of the DFT method has shown that they can successfully solve similar problems and answer questions from sensor developers [32][33][34]. In particular, a numerical experiment using DFT methods makes it possible to determine the activation barrier, the change in free energy and the position of the Fermi level when gas molecules land on the sensor surface, and to predict the effect of moisture and other types of surface modification.…”