Mohamed Mohamed Mokhtar, El-Farsy Hassan
Chemistry Department, Faculty of Science, Benha University, Benha, Egypt.
Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt.
Sci Rep. 2020 Dec 9;10(1):21495. doi: 10.1038/s41598-020-78542-5.
A novel photocatalyst based on the design of P-N heterojunction between hollow spherical MnO and nanorods shape of α-AgWO is synthesized using a sonication-deposition-precipitation route. The nanocomposite MnO/α-AgWO(60%) exhibits a great potential towards nitroarenes (including 4-nitrophenol, 4-nitro-aniline and 4-Nitro-acetanilide) reduction under visible light irradiation exceeding that of MnO/α-AgWO(40%) as well as their individual counterparts (3-5%). The MnO/α-AgWO(60%) catalyst exhibited an excellent photo-reduction activity comprised of 0.067 s towards 4-nitrophenol (0.001 M) in only 60 s reaction time using NaBH (0.2 M). This was due to the successful formation of the MnO/α-AgWO composite as validated by XRD, TEM-SAED, XPS, FTIR, UV-Vis diffuse reflectance and PL techniques. Decreasing the E value into 2.7 eV, the existence of a new (151) plane in the composite beside enhancement of the composite electrical conductivity (1.66 × 10 Ω cm) helps the facile nitroarenes adsorption and hydrogenation. Transient photocurrent response and linear sweep voltammetry results prove the facilitation of photogenerated charge carriers separation and transport via improving electron lifetime and lessening recombination rate. The composite photocatalyst produced higher amounts of H production, when inserted in a typical reaction medium containing NaBH, comprised of 470 µ mole/g exceeding those of the counterparts (35 µ mole/g). This photocatalyst is strikingly hydrogenated 4-nitrophenol under mild conditions (25 °C and 0.35 MPa pressure of H) with magnificent rate constant equal 34.9 × 10 min with 100% selectivity towards 4-aminophenol.
采用超声沉积-沉淀法合成了一种基于空心球形MnO与纳米棒状α-AgWO4之间P-N异质结设计的新型光催化剂。纳米复合材料MnO/α-AgWO4(60%)在可见光照射下对硝基芳烃(包括4-硝基苯酚、4-硝基苯胺和4-硝基乙酰苯胺)还原表现出巨大潜力，超过了MnO/α-AgWO4(40%)及其各自对应物(3-5%)。MnO/α-AgWO4(60%)催化剂在仅60秒的反应时间内，使用NaBH4(0.2M)对4-硝基苯酚(0.001M)表现出优异的光还原活性，速率为0.067 s-1。这是由于通过XRD、TEM-SAED、XPS、FTIR、UV-Vis漫反射和PL技术验证了MnO/α-AgWO4复合材料的成功形成。将E值降低到2.7 eV，复合材料中除了提高复合电导率(1.66×10-3Ω·cm)外还存在新的(151)平面，有助于硝基芳烃的吸附和氢化。瞬态光电流响应和线性扫描伏安法结果证明，通过提高电子寿命和降低复合率促进了光生载流子的分离和传输。当插入含有NaBH4的典型反应介质中时，复合光催化剂产生了更高量的H₂产量，为470 μmol/g，超过了对应物(35 μmol/g)。这种光催化剂在温和条件(25°C和0.35 MPa H₂压力)下能显著氢化4-硝基苯酚，速率常数高达34.9×10-3 min-1，对4-氨基苯酚的选择性为100%。
