Ag3PO4/羟基磷灰石复合光催化剂的制备及对亚甲基蓝的高效降解

Preparation of Ag3PO4/HAP composite photocatalyst and its efficient degradation of methylene blue

以天然废弃物牡蛎壳为原料,利用沉淀法和水热法制备出高纯度的羟基磷灰石(HAP),负载Ag3PO4后制备出具有可见光响应的复合光催化剂Ag3PO4/HAP,并以亚甲基蓝(MB)为反应模型考察了不同催化剂的降解性能。利用SEM、TEM、XRD、BET、XPS、UV-Vis、电子自旋共振(ESR)等仪器对样品进行表征。结果表明,两种方法均可合成HAP材料,但水热法合成的材料纯度更高,且合成出了纳米等级的HAP;Ag3PO4的添加未改变HAP的组成和结构,却改善了材料对可见光的吸收性能。与沉淀法相比,水热法制备的HAP具有更好的吸附性能,其比表面积为46.63 m2·g^-1;且随着Ag3PO4质量的增加,复合材料的比表面积逐渐增大。水热法制备的Ag3PO4/HAP表现出了较高的活性,其中1:2-Ag3PO4/HAP催化剂的表现更突出,在10 min时即可达到50%的降解率,并在40 min内达到完全降解;经自由基捕获实验证实,参与降解反应的主要活性物种为·O2^-和h^+。

High purity hydroxyapatite(HAP)was synthesized via the precipitation method and hydrothermal method,with oyster shells as raw material.After Ag3PO4 particles were loaded on the HAP support,the Ag3PO4/HAP photocatalysts show a pronounced photocatalytic activity upon decomposition of methylene blue(MB)dye in aqueous solution under visible light.The as-synthesized samples were characterized by SEM,TEM,XRD,BET,XPS,UV-Vis and electron spin resonance(ESR).The results show that HAP could be synthesized by both methods,but higher purity and nano-sized HAP are synthesized by the hydrothermal method.The addition of Ag3PO4 does not change the composition and structure of HAP,but improves its absorption property of visible light.Compared with the precipitation method,hydrothermal prepared HAP has the better adsorption performance,and its specific surface area is 46.63 m2·g^-1.And the specific surface areas of Ag3PO4/HAP composites(hydrothermal method)increase gradually with the increase of Ag3PO4 content.Therefore,the hydrothermal preparation of Ag3PO4/HAP shows higher activity,and the 1:2-Ag3PO4/HAP produces the highest photocatalytic activity;its degradation rate of MB is up to 50%within 10 min of irradiation and its complete degradation is almost done at 40 min.The free radical capture experiment confirms that the main active species involved in the degradation reaction are•O2^−and h^+.