Perspectives on Advances in the Catalytic Desulfurization and Denitrogenation of Transportation Fuel Oils Using Graphitic Carbon Nitride and Boron Nitride

Abstract

Expulsion of sulfur-containing compounds as well as nitrogen-containing compounds present in fuel oils is critical because it can cause numerous environmental problems and catalyst deactivation. Because of the limitations of the other catalysts and adsorbents used for desulfurization, a new type of carbon material, i.e., graphitic carbon nitride (g-C3N4), has emerged. It is similar in morphology to graphene having a two-dimensional structure and possessing a band gap of 2.7 eV and is an attractive catalyst attributed to its intriguing characteristics like high intrinsic photoresponsiveness and photoabsorption, semiconductive properties, and better stability. An ample amount of literature has been documented on g-C3N4 applied for the desulfurization and denitrogenation of fuel oils. Due to the analogy of boron with carbon materials, boron nitrides (BN) are also important. In materials chemistry, hexagonal BN (h-BN), often termed as “white graphene”, among the different phases of BN, is highly regarded due to adaptation of diverse morphologies such as nanotubes and nanosheets. BN has been recommended as an emerging and efficacious 2D material in catalysis because it possesses oxidative resistance, chemically inertness, a sp2-bonded layered structure, wide band gap, and higher thermal stability and conductivity. This review systematically encompasses the important reports documented on the applications of g-C3N4 and BNs in fuel oil processing including the synthesis, various properties, and fascinating experimental findings. Later on, key suggestions are put forward for future research directions and new technologies applying g-C3N4 and BN for the processing of transportation fuels. This review could act as a concentrated platform, as a quick access source and great degree of convenience, giving time effective routes for researchers to reported results and designs of novel and efficacious catalysts for the commercialization of desulfurization and denitrogenation technologies.

A Nickel-Doped Dehydrobenzoannulene-Based Porous Organic Polymer for the Catalytic Desulfurization of Dibenzothiophenes and Benzothiophenes

“…have been utilized over the past several decades to activate and cleave C–S bonds. However, these catalytic systems are expensive and often suffer from poor chemoselectivity, low catalytic efficiency, and low recyclability which greatly limits their long-term use as desulfurization catalysts …”

“…However, these catalytic systems are expensive and often suffer from poor chemoselectivity, low catalytic efficiency, and low recyclability which greatly limits their long-term use as desulfurization catalysts. 16 Recently, our lab has shown that a covalent organic framework (COF) 17−19 containing dehydrobenzoannulene (DBA)-Ni(0) complexes can be used to reductively cleave the C(aryl)-S bonds of several organosulfur compounds utilizing hydrosilanes as the reducing agent. 20 While this catalytic system was recyclable and great for activating C(aryl)-S bonds of fused and unfused aryl thioethers, it is still unclear if this Ni(0)-based catalytic system is useful for the desulfurization of dibenzothiophenes (DBTs), a class of refractory sulfur compounds that are commonly found in sour crude oil.…”

“…21 Unlike aryl thioethers, DBTs are not very reactive and they account for the highest percentage of sulfur compounds found in heavy and vacuum gas oil that must be removed to meet environmental standards. 2,16,21,22 Interestingly, Garcia and coworkers have shown that Ni catalysts like [(dippe)-NiH)] 2 are great for the desulfurization of DBTs in the presence of alkyl Grignards. 23,24 While the system is believed to proceed through a classical Ni(0)/Ni(II) pathway, the sulfur gets converted initially to MgS and then to H 2 S after an acidic workup.…”

Ionic Liquid Promotes High Dispersion of V2O5 on 3D Porous g-C3N4 Carrier to Enhance Catalytic Oxidative Desulfurization Performance

“…The problem of agglomeration is an urgent matter to be solved, as is the case with other TMOs. A feasible strategy is to select an appropriate porous carrier to construct supported catalysts. , Carbon nitride (g-C 3 N 4 ) has a simple preparation process and high yield and is often used as a carrier in supported catalysts . In comparison, three-dimensional porous carbon nitride (3D g-C 3 N 4 ) obtained by the supramolecular assembly method, with a rich pore structure and high specific surface area, is a more suitable carrier …”

“…6,7 Carbon nitride (g-C 3 N 4 ) has a simple preparation process and high yield and is often used as a carrier in supported catalysts. 8 In comparison, three-dimensional porous carbon nitride (3D g-C 3 N 4 ) obtained by the supramolecular assembly method, with a rich pore structure and high specific surface area, is a more suitable carrier. 9 Ionic liquids (ILs) have many excellent properties, which have been widely studied by researchers since their discovery.…”