Ammonium perchlorate (AP) catalytic thermal decomposition by metal oxides is complex and there is still no suitable quantitative evaluation method to characterize intrinsic catalytic activity. Here, a new method to quantitatively evaluate the catalytic capability of metal oxides for AP decomposition has been proposed. We introduce two indicators, intrinsic peak temperature ($T_{\mathrm{HTD}}^{*}$𝑇∗HTD$T_{\mathrm{HTD}}^{*}$) and catalytic density (${\rho }_{T^{*}}$𝜌𝑇∗${\rho }_{T^{*}}$) in high-temperature decomposition process, to uncouple activity and number of catalyst sites. Hematite (α-Fe₂O₃) nanostructures with different shapes have been used as model catalysts to verify the feasibility of this method. Rod-like α-Fe₂O₃ shows the best catalytic performance in AP decomposition with the lowest $T_{\mathrm{HTD}}^{*}$𝑇∗HTD$T_{\mathrm{HTD}}^{*}$ of 345.1°C and highest ${\rho }_{T^{*}}$𝜌𝑇∗${\rho }_{T^{*}}$ of 0.544, which indicate the largest number and highest activity of catalytic sites. Moreover, these new indicators are theoretically proven to be reasonable by density functional theory calculations.

中文翻译：

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定量评估金属氧化物上高氯酸铵分解的活性和催化位点数量

金属氧化物催化高氯酸铵（AP）的热分解是复杂的，目前还没有合适的定量评价方法来表征内在催化活性。在这里，已经提出了一种定量评估金属氧化物对 AP 分解的催化能力的新方法。我们引入两个指标，内在峰值温度（${吨}_{\mathrm{HTD}}^{*}$𝑇*HTD$T_{\mathrm{HTD}}^{*}$) 和催化密度 (${\rho }_{{吨}^{*}}$𝜌𝑇*${\rho }_{T^{*}}$) 在高温分解过程中，以解耦活性和催化剂位点的数量。以不同形状的赤铁矿（α-Fe ₂ O ₃）纳米结构为模型催化剂，验证了该方法的可行性。棒状α-Fe ₂ O ₃在AP分解中表现出最好的催化性能，最低${吨}_{\mathrm{HTD}}^{*}$𝑇*HTD$T_{\mathrm{HTD}}^{*}$345.1°C 和最高${\rho }_{{吨}^{*}}$𝜌𝑇*${\rho }_{T^{*}}$0.544，这表明催化位点的数量和活性最高。而且，这些新指标通过密度泛函理论计算在理论上证明是合理的。