Akir Sana, Azadmanjiri Jalal, Antonatos Nikolas, Děkanovský Lukáš, Roy Pradip Kumar, Mazánek Vlastimil, Lontio Fomekong Roussin, Regner Jakub, Sofer Zdeněk
Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.
Nanoscale. 2023 Aug 3;15(30):12648-12659. doi: 10.1039/d3nr01144e.
The exploitation of two-dimensional (2D) vanadium carbide (VCT, denoted as VC) in electrocatalytic hydrogen evolution reaction (HER) and nitrogen reduction reaction (NRR) is still in the stage of theoretical study with limited experimental exploration. Here, we present the experimental studies of VC MXene-based materials containing two different bismuth compounds to confirm the possibility of using VC as a potential electrocatalyst for HER and NRR. In this context, for the first time, we employed two different methods to synthesize 2D/0D and 2D/2D nanostructures. The 2D/2D VC/BVO consisted of BiVO (denoted BVO) nanosheets wrapped in layers of VC which were synthesized by a facile hydrothermal method, whereas the 2D/0D VC/Bi consisted of spherical particles of Bi (Bi NPs) anchored on VC MXenes using the solid-state annealing method. The resultant VC/BVO catalyst was proven to be beneficial for HER in 0.5 M HSO compared to pristine VC. We demonstrated that the 2D/2D VC/BVO structure can favor the higher specific surface area, exposure of more accessible catalytic active sites, and promote electron transfer which can be responsible for optimizing the HER activity. Moreover, VC/BVO has superior stability in an acidic environment. Whilst we observed that the 2D/0D VC/Bi could be highly efficient for electrocatalytic NRR purposes. Our results show that the ammonia (NH) production and faradaic efficiency (FE) of VC/Bi can reach 88.6 μg h cm and 8% at -0.5 V RHE, respectively. Also VC/Bi exhibited excellent long-term stability. These achievements present a high performance in terms of the highest generated NH compared to recent investigations of MXenes-based electrocatalysts. Such excellent NRR of VC/Bi activity can be attributed to the effective suppression of HER which is the main competitive reaction of the NRR.
二维碳化钒（VCT，记为VC）在电催化析氢反应（HER）和氮还原反应（NRR）中的应用仍处于理论研究阶段，实验探索有限。在此，我们展示了含两种不同铋化合物的基于VC MXene材料的实验研究，以证实将VC用作HER和NRR潜在电催化剂的可能性。在此背景下，我们首次采用两种不同方法合成二维/零维（2D/0D）和二维/二维（2D/2D）纳米结构。2D/2D VC/BVO由包裹在VC层中的钒酸铋（记为BVO）纳米片组成，通过简便的水热法合成，而2D/0D VC/Bi由使用固态退火法锚定在VC MXene上的铋球形颗粒（Bi NPs）组成。结果表明，与原始VC相比，所得的VC/BVO催化剂在0.5 M硫酸中对HER有益。我们证明2D/2D VC/BVO结构有利于更高的比表面积、更多可及催化活性位点的暴露，并促进电子转移，这有助于优化HER活性。此外，VC/BVO在酸性环境中具有优异的稳定性。同时，我们观察到2D/0D VC/Bi对电催化NRR目的可能非常高效。我们的结果表明，在 -0.5 V 可逆氢电极（RHE）下，VC/Bi的氨（NH₃）产量和法拉第效率（FE）分别可达88.6 μg h⁻¹ cm⁻²和8%。此外，VC/Bi表现出优异的长期稳定性。与最近基于MXene的电催化剂研究相比，这些成果在产生的最高NH₃量方面表现出高性能。VC/Bi如此优异的NRR活性可归因于对HER的有效抑制，HER是NRR的主要竞争反应。
