Platinum loaded tin dioxide: a model system for unravelling the interplay between heterogeneous catalysis and gas sensing

Degler, David; Müller, Sabrina; Doronkin, Dmitry E.; Wang, Di; Grunwaldt, Jan‐Dierk; Weimar, Udo; Bârsan, Nicolae

doi:10.1039/c7ta08781k

Cited by 95 publications

(80 citation statements)

References 43 publications

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“…The DRIFTS spectra of both materials show that the reaction of CO is no longer taking place on the SnO2 surface and, thus, is shifted to the noble metal clusters. These findings suggest a sensitization by a Fermi-level control mechanism, as recently reported for Pt loaded SnO2 or Rh loaded WO3 [26,47].…”

Section: Resultssupporting

confidence: 85%

“…In humid air water vapor inhibits both reactions, but the inhibiting effect is stronger for the reoxidation and, thus, the sensor signals increase compared to dry air, while the catalytic activity of the material decreases [26]. A strong difference between the CH4 gas response of Au/SnO2 and Pd/SnO2 is observed.…”

Section: Pd-loaded Samplesmentioning

confidence: 91%

“…The second generally accepted sensitization mechanism is the Fermi-level control mechanism, which is expected for oxidized metal loading like in the case of Pt [19,26] or Pd [27,28] The strength of this coupling is determined by the stoichiometry of the noble metal loading, i.e.…”

Section: Energy Resolution Fluorescence Detection X-ray Absorption Spmentioning

confidence: 99%

“…also present in an inert atmosphere. Thus, by comparing the resistances of the noble metal loaded materials with the corresponding values for pristine SnO2 allows estimating the initial band bending using the following equation [26,47],…”

Section: Electronic Effects Of the Loadingsmentioning

confidence: 99%

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Microfluidically synthesized Au, Pd and AuPd nanoparticles supported on SnO2 for gas sensing applications

Tofighi

Degler

Junker

et al. 2019

Sensors and Actuators B: Chemical

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Monometallic Au and Pd nanoparticles (NPs) and homogeneous AuPd nanoalloy particles were synthesized in a continuous flow of reactants (HAuCl4, K2PdCl4, NaBH4 and polyvinylpyrrolidone (PVP)) using a microfluidic reactor with efficient micromixers. The obtained ultrasmall NPs were subsequently deposited onto SnO2 supports with different surface area (32.7 and 3.6 m 2 g-1). Samples with 1.0 and 0.1 wt.% metal loading were prepared. After calcination at 380 °C for 1 h the supported NPs aggregated to some extent. SnO2 supported AuPd nanoalloys with low (0.1 wt.%) metal loadings showed the smallest NP diameters (~ 5-7 nm) and the narrowest size distribution among the samples. The gas sensing performance of the materials was investigated at 300 °C in four different gas atmospheres containing either CO, CH4, ethanol or toluene using dry and humid conditions. They exhibited a distinct variation in the response patterns and selectivity toward the test gases depending on composition and metal loading: Au increased the sensor signals compared to pristine SnO2 in all cases and decreased the interference of water vapor; the supported Pd NPs showed a weak response to toluene, strong sensitivity in CO sensing and slightly better response in ethanol sensing in humid air compared to dry air. However, they showed a high selectivity toward CH4 when used in dry air; AuPd alloy particles provided lower sensor signals compared to pristine SnO2 and no remarkable CH4 selectivity, in contrast to the Pd system. Operando diffuse reflectance infrared Fourier-transformed spectroscopy (DRIFTS) indicates a strong band bending in the case of Pd and AuPd NPs, whereas in the case of Au no band bending occured, indicating a strong electronic interaction between the support and Pd-containing NPs (Fermi-level control mechanism), and a weak electronic interaction between SnO2 and Au NPs (spill-over mechanism).

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Section: Resultssupporting

confidence: 85%

Section: Pd-loaded Samplesmentioning

confidence: 91%

Section: Energy Resolution Fluorescence Detection X-ray Absorption Spmentioning

confidence: 99%

Section: Electronic Effects Of the Loadingsmentioning

confidence: 99%

See 2 more Smart Citations

Microfluidically synthesized Au, Pd and AuPd nanoparticles supported on SnO2 for gas sensing applications

Tofighi

Degler

Junker

et al. 2019

Sensors and Actuators B: Chemical

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“…In order to gain fundamental insights on this topic, 0.5 and 1 at% Rh2O3-loaded In2O3, were chosen as model samples-the investigating approach is inspired by the work described in [1,2], because it was demonstrated that it helped the prevalence of a Fermi-level control mechanism that explained the gas sensing performance. Besides the loaded samples, an unloaded one was used as a reference; all sensors were operated at 300 °C.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Sensing Mechanism of Rh2O3 loaded In2O3

Boehme¹,

Herrmann²,

Staerz³

et al. 2018

Eurosensors 2018

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The effect of Rh loading on CO sensing was studied for the case of In2O3. This was done by performing measurements with sensors based on loaded and unloaded materials that were performed at an operation temperature of 300 °C in the presence of low background oxygen concentration according to an experimental procedure that was demonstrated to help clarify the reception/transduction functions of loaded Semiconducting Metal Oxides (SMOX). The experimental investigation methods were DC resistance and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that in the case of Rh2O3 loaded In2O3 the reaction primary takes place on the Rh2O3 cluster and the electrical properties of the In2O3 are controlled by the pinning of the SMOX Fermi-level to the one of the Rh2O3 cluster.

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Sacrificial Template‐Assisted Synthesis of Inorganic Nanosheets with High‐Loading Single‐Atom Catalysts: A General Approach

Shin

Park

et al. 2021

Adv Funct Materials

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Single‐atom catalysts (SACs) supported on inorganic materials have attracted much attention in numerous research fields for their high catalytic performance. However, such SACs have been limited by the low metal loading, especially on different types of inorganic supports. Herein, a general approach is presented for preparing SACs on metallic, metal oxide, and perovskite nanosheet (NS) supports to reach a high metal loading of up to 3.94 wt%, by utilizing N‐doped graphene as a sacrificial template that spatially confines the single atoms (SAs). Specifically, the target support material precursors are adsorbed onto the SAs‐stabilized sacrificial template, followed by subsequent heat treatment to transfer the SAs to the support material and to remove the graphene layer. Pt SAs on oxide support exhibits little to no aggregation throughout >10 000 min of annealing at 275 °C, demonstrating high thermal stability, as also supported by ex situ post‐anneal electron microscopy and X‐ray absorption fine structure studies. As a proof‐of‐concept, Pt SACs on SnO2 NSs exhibit high catalytic activity toward chemiresistive sensing of acetone gas (response = 95.4 at 10 ppm, 7.6‐fold enhancement compared with pristine SnO2 NSs) and unprecedented stability under highly humid conditions (27.4% response deterioration at 95% relative humidity).

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Platinum loaded tin dioxide: a model system for unravelling the interplay between heterogeneous catalysis and gas sensing

Abstract: The presented work unravels the complex structure–function-relationships of Pt-loaded SnO2, namely the sensitization by a Fermi-control mechanism and relation of catalytic activity and gas sensing effect.

Cited by 95 publications

References 43 publications

Microfluidically synthesized Au, Pd and AuPd nanoparticles supported on SnO2 for gas sensing applications

Microfluidically synthesized Au, Pd and AuPd nanoparticles supported on SnO2 for gas sensing applications

Understanding the Sensing Mechanism of Rh2O3 loaded In2O3

Sacrificial Template‐Assisted Synthesis of Inorganic Nanosheets with High‐Loading Single‐Atom Catalysts: A General Approach

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