From E‐Waste to Nb‐Pb Co‐Doped and Pd‐Loaded TiO₂/BaTiO₃ Heterostructure: Highly Efficient Photocatalytic Performance

Abstract

A new and sustainable process was reported for the in situ synthesis of Nb‐Pb co‐doped and Pd‐loaded TiO2/BaTiO3 nanometer heterostructures from waste multilayer ceramic capacitors through a simple chlorination–leaching route. The particle size of the Nb‐Pb co‐doped heterostructure and the Pd loading were 20–50 nm and less than 5 nm, respectively. The bandgaps of the prepared samples were in the range 2.81–2.92 eV. The optimal simulated‐sunlight photocatalytic H2 production rate and Rhodamine B degradation rate of the prepared heterostructure could reach 576.8 μmol g−1 h−1 and 0.29911 min−1, respectively, which were approximately 11.3 and 19.1 times higher than those of commercial TiO2, and 5.96 and 8.91 times higher than those of bare TiO2/BaTiO3. The recycled heterostructure exhibited excellent photostability and reusability. Such superior photocatalytic performance of the sample was attributed to the formation of the heterostructure, the Nb‐Pb co‐doping, and the Pd loading, which enhanced the visible light absorption and charge separation efficiency. Furthermore, DFT calculations were applied to explore the enhanced mechanism. This study demonstrates a sustainable process for the conversion of e‐waste to a high‐value‐added and highefficiency photocatalyst, which has the advantages of waste utilization, low‐cost preparation, and environmental protection.

Photocatalytic degradation of Perchloroethylene by a lab-scale continuous-flow annular photoreactor packed with glass beads carbon-doped TiO2 nanoparticles

“…Supporting on materials with large surface areas such as glass fiber [15], paint [16], thin-film TiO 2 [17], TiO 2 pellet [18], carbon black or activated carbon [19], carbon nanofibers [20], carbon nanotube [21] is one approach. Another trend is combining or doping TiO 2 with other materials such as Ag [22], Au [23], Sn [24], Pb [25], Ni [26] metal oxides [27] to improve the performance of the photocatalyst. Among these attempts, TiO 2 doping with transition metals ions such as V, Co, or Fe has been a common approach for improving the photocatalytic performance of the catalyst.…”

Photocatalytic Materials Obtained from E-Waste Recycling: Review, Techniques, Critique, and Update

“…Note that BaTiO3 is generally used to degrade organic pollutants and split the water [109,110]. Niu and Xu [111] successfully produced a Nb-Pb-co-doped and Pd-loaded TiO2/BaTiO3 heterostructure by the in situ synthesis of MLCCs through the facile chlorination-leaching process, showing great photostability and reusability due to Nb-Pb co-doping, heterostructure formation, and the Pd loading. Figure 8 shows the MLCC structure having many BaTiO3 dielectric layers and stacked internal electrodes.…”

“…Figure 8 shows the MLCC structure having many BaTiO3 dielectric layers and stacked internal electrodes. In Figure 8, the simple chlorination-leaching process which resulted in the high throughput formation of Nb-Pb-co-doped and Pdloaded TiO2/BaTiO3 heterostructure is shown [111]. The chlorination step was performed in a quartz tube furnace in which NH4Cl and scrap powder with determined mass ratios of (0.5-4):1 was mixed and then heated at 500 °C for 30 min under air.…”

“…The TiO2 sample (NH4Cl/scrap:4) has the greatest H2 evolution rate, an enhanced activity which can be related to co-doping with Nb-Pb, enhanced the visible light absorption, and has effective charge separation [112,113]. Niu and Xu [111] proposed a novel method for the in situ fabrication of Nb-Pb-co-doped and Pd-loaded TiO2/BaTiO3 nanostructured heterostructures from e-waste (multilayer ceramic capacitors) by a chlorination-leaching route. TiO2based photocatalysts from e-waste can be a great option to solve environmental pollution [114].…”

“…The photocatalytic degradation of RhB was also analyzed under simulated sunlight. Even though all the samples exhibited favorable photocatalytic activity toward RhB degradation, it was seen that the catalyst had a negligible impact on the degradation of RhB [111]. Niu et al [117] proposed a new approach to magnetically generate core-shell Zscheme Nb-Pb-co-doped BaTiO3/Ni-Pd@g-C3N4 photocatalysts using the ceramic capacitor e-waste for H2 production.…”