Microwatt-Resolution Calorimeter for Studying the Reaction Thermodynamics of Nanomaterials at High Temperature and Pressure,ACS Sensors

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Microwatt-Resolution Calorimeter for Studying the Reaction Thermodynamics of Nanomaterials at High Temperature and Pressure
ACS Sensors ( IF 8.2 ) Pub Date : 2020-11-23 , DOI: 10.1021/acssensors.0c01550
Amin Reihani ₁ , Ju Won Lim ₂ , David K. Fork ₃ , Edgar Meyhofer ₁ , Pramod Reddy _{1,

2}

Affiliation

Calorimetry of reactions involving nanomaterials is of great current interest, but requires high-resolution heat flow measurements and long-term thermal stability. Such studies are especially challenging at elevated reaction pressures and temperatures. Here, we present an instrument for measuring the enthalpy of reactions between gas-phase reactants and milligram scale nanomaterial samples. This instrument can resolve the net change in the amount of gas-phase reactants due to surface reactions in an operating range from room temperature to 300 °C and reaction pressures of 10 mbar to 30 bar. The calorimetric resolution is shown to be <3 μW/√Hz, with a long-term stability <4 μW/hour. The performance of the instrument is demonstrated via a set of experiments involving H₂ absorption on Pd nanoparticles at various pressures and temperatures. For this specific reaction, we obtained a mass balance resolution of 0.1 μmol/√Hz. Results from these experiments are in good agreement with past studies establishing the feasibility of performing high resolution calorimetry on milligram scale nanomaterials, which can be employed in future studies probing catalysis, phase transformations, and thermochemical energy storage.

中文翻译：

微波分辨量热仪用于研究高温高压下纳米材料的反应热力学

涉及纳米材料的反应的量热法目前引起人们极大的兴趣，但需要高分辨率的热流测量和长期的热稳定性。在升高的反应压力和温度下，此类研究尤其具有挑战性。在这里，我们介绍了一种用于测量气相反应物和毫克级纳米材料样品之间反应焓的仪器。该仪器可解决在室温至300°C的工作范围内以及10 mbar至30 bar的反应压力下由于表面反应而引起的气相反应物量的净变化。量热分辨率显示为<3μW/√Hz，长期稳定性<4μW/小时。通过一系列涉及H ₂的实验证明了该仪器的性能。在各种压力和温度下对Pd纳米颗粒的吸收。对于该特定反应，我们获得的质量平衡分辨率为0.1μmol/√Hz。这些实验的结果与以往的研究非常吻合，建立了对毫克级纳米材料进行高分辨率量热的可行性，可用于未来研究催化，相变和热化学能量存储的研究。

更新日期：2020-11-23

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