Hydroxyapatite (HAP) was reported to promote photocatalytic degradation as a support for photocatalysts, but the enhancement mechanism is still unclear. In this study, the promotion role of HAP to TiO₂ in photocatalytic degradation is unraveled using experimental observations and kinetic modeling. TiO₂/HAP is successfully synthesized by a facile hydrothermal method, which is confirmed by SEM-EDS, TEM, ICP, XRD, and Raman. HAP exhibits a negative effect on the photo absorption ability of TiO₂/HAP, which is characterized by UV–vis reflectance spectra (Tauc plot). The formaldehyde-temperature programmed desorption results reveal an affinity between HAP and formaldehyde via a weak chemisorption, which is validated by the estimated adsorption enthalpy/entropy from Van't Hoff plot based on Langmuir–Hinshelwood model. The derived kinetic parameters, including reaction rate constant, Langmuir adsorption constant, apparent activation energy, and adsorption enthalpy and entropy, confirm the experimental results that TiO₂/HAP is more active than TiO₂. This work verifies the existence of superior chemisorption between HAP and VOCs leading to a better performance of TiO₂/HAP for photocatalytic degradation. It helps to understand the role of HAP as an effective support in designing novel HAP-based catalysts.

据报道，羟基磷灰石（HAP）可以促进光催化降解，以作为光催化剂的载体，但增强机理仍不清楚。在这项研究中，HAP对TiO ₂的促进作用在光催化降解中的作用尚不能通过实验观察和动力学建模来阐明。通过简便的水热法成功地合成了TiO ₂ / HAP，并通过SEM-EDS，TEM，ICP，XRD和Raman证实了该方法。HAP对TiO ₂的光吸收能力有负面影响/ HAP，其特征在于紫外可见反射光谱（Tauc图）。甲醛温度程序解吸结果显示了HAP与甲醛之间通过弱化学吸附而产生的亲和力，这已通过基于Langmuir-Hinshelwood模型的Van't Hoff图估算的吸附焓/熵得到了验证。推导的动力学参数，包括反应速率常数，Langmuir吸附常数，表观活化能以及吸附焓和熵，证实了TiO ₂ / HAP比TiO ₂更具活性的实验结果。这项工作验证了HAP和VOC之间存在优异的化学吸附作用，从而导致TiO ₂的更好性能/ HAP用于光催化降解。它有助于了解HAP在设计新型基于HAP的催化剂方面的有效支持作用。