Itskou Ioanna, Kafizas Andreas, Nevjestic Irena, Carrero Soranyel Gonzalez, Grinter David C, Azzan Hassan, Kerherve Gwilherm, Kumar Santosh, Tian Tian, Ferrer Pilar, Held Georg, Heutz Sandrine, Petit Camille
Barrer Centre, Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K.
Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London W12 7TA, U.K.
J Phys Chem C Nanomater Interfaces. 2024 Jul 24;128(31):13249-13263. doi: 10.1021/acs.jpcc.4c02314. eCollection 2024 Aug 8.
Amorphous porous boron nitride (BN) represents a versatile material platform with potential applications in adsorptive molecular separations and gas storage, as well as heterogeneous and photo-catalysis. Chemical doping can help tailor BN's sorptive, optoelectronic, and catalytic properties, eventually boosting its application performance. Phosphorus (P) represents an attractive dopant for amorphous BN as its electronic structure would allow the element to be incorporated into BN's structure, thereby impacting its adsorptive, optoelectronic, and catalytic activity properties, as a few studies suggest. Yet, a fundamental understanding is missing around the chemical environment(s) of P in P-doped BN, the effect of P-doping on the material features, and how doping varies with the synthesis route. Such a knowledge gap impedes the rational design of P-doped porous BN. Herein, we detail a strategy for the successful doping of P in BN (P-BN) using two different sources: phosphoric acid and an ionic liquid. We characterized the samples using analytical and spectroscopic tools and tested them for CO adsorption and photoreduction. Overall, we show that P forms P-N bonds in BN akin to those in phosphazene. P-doping introduces further chemical/structural defects in BN's structure, and hence more/more populated midgap states. The selection of P source affects the chemical, adsorptive, and optoelectronic properties, with phosphoric acid being the best option as it reacts more easily with the other precursors and does not contain C, hence leading to fewer reactions and C impurities. P-doping increases the ultramicropore volume and therefore CO uptake. It significantly shifts the optical absorption of BN into the visible and increases the charge carrier lifetimes. However, to ensure that these charges remain reactive toward CO photoreduction, additional materials modification strategies should be explored in future work. These strategies could include the use of surface cocatalysts that can decrease the kinetic barriers to driving this chemistry.
非晶态多孔氮化硼（BN）是一种多功能材料平台，在吸附性分子分离、气体存储以及多相催化和光催化领域具有潜在应用价值。化学掺杂有助于调整BN的吸附、光电和催化性能，最终提升其应用性能。磷（P）是一种有吸引力的非晶态BN掺杂剂，因为一些研究表明，其电子结构能使该元素融入BN结构，从而影响其吸附、光电和催化活性特性。然而，目前对于P掺杂BN中P的化学环境、P掺杂对材料特性的影响以及掺杂如何随合成路线变化仍缺乏基本认识。这种知识缺口阻碍了P掺杂多孔BN的合理设计。在此，我们详细介绍了一种使用两种不同来源（磷酸和离子液体）成功将P掺杂到BN（P-BN）中的策略。我们使用分析和光谱工具对样品进行了表征，并测试了它们对CO的吸附和光还原性能。总体而言，我们发现P在BN中形成了类似于磷腈中的P-N键。P掺杂在BN结构中引入了更多化学/结构缺陷，进而产生了更多占据中间能隙的状态。P源的选择会影响化学、吸附和光电性能，磷酸是最佳选择，因为它更容易与其他前驱体反应且不含C，因此反应和C杂质更少。P掺杂增加了超微孔体积，从而提高了CO的吸附量。它显著将BN的光吸收转移到可见光区域，并延长了电荷载流子寿命。然而，为确保这些电荷对CO光还原仍具有反应活性，未来工作中应探索其他材料改性策略。这些策略可能包括使用能降低驱动该化学反应动力学势垒的表面助催化剂。
