Reaction rate and thermal effects of hydrogen peroxide decomposition in microfluidic chips containing channel-type silver catalysts

Abstract

As an important application of microfluidic chips, liquid chemical microthrusters need to introduce a structured catalyst block in the design process. In this paper, a structured silver catalyst is used to promote the decomposition of hydrogen peroxide in microfluidic chips. In addition, the temperature of the microchannel on the microfluidic chip is controlled in real time by the planar electric heating plate, and the temperature of the catalytic decomposition reaction of the hydrogen peroxide reaction liquid is monitored in real time by an infrared thermal imaging camera. The reaction rate of catalytic decomposition of hydrogen peroxide was indirectly detected online by an ultraviolet-visible spectrophotometer. The experimental results show that when the temperature of the microfluidic chip exceeds 70 °C, the thermal decomposition rate of hydrogen peroxide in the microchannel on the preheating region gradually dominates and cannot be ignored. When the quadratic regression orthogonal experiment was used to study the influence of 1/T, ln t and ln c₀ on ln r, it was found that ln c₀ had a significant effect on ln r, and (1/T) × ln t and (ln t)² had a significant effect on ln r. And within the experimental study range, when T = 333.16 K, t = 0.02 ms and c₀ = 3 mol L⁻¹, the maximum value of ln r was obtained, and it was 454.5 ± 8.2 mol L⁻¹ s⁻¹. In the single factor study, it can be seen that the temperature of the hot plate and the initial concentration of hydrogen peroxide are positively correlated with the reaction rate of hydrogen peroxide-catalyzed decomposition. The reaction rate of catalytic decomposition of hydrogen peroxide decreases first and then increases with the increase of flow rate. The study of the thermal effect and catalytic performance of microfluidic chips provides a reference value for the design and application of microfluidic chips in microthrusters.