# An Experimental Study of Glycerol Carbonate Synthesis over g-C\({}_{3}\)N\({}_{4}\) Catalysts
## 1 Introduction
ZnAlCe catalysts were obtained by co-precipitation [22], while gold nanoparticles (AuNPs) were incorporated into a metal-organic framework (MOF) constructed from mixed carboxylate linkers, including terephthalatic acid and 1,3,5-benzetricarboxylic acid [23]. La\({}_{2}\)O\({}_{2}\)CO\({}_{3}\)/ZnO catalysts were created through both co-precipitation and ethylene glycol combustion methods [24], and metal oxides such as MgO, CaO, and Al\({}_{2}\)O\({}_{3}\) were synthesized via precipitation [25]. Finally, phosphorus and sulfurco-doped graphitic carbon nitride (g-C\({}_{3}\)N\({}_{4}\)) was produced through a one-step thermal condensation process [26]. Graphitic carbon nitride (g-C\({}_{3}\)N\({}_{4}\)) has drawn considerable interest for its potential to tackle energy and environmental issues. Its electron-rich framework, surface basicity, and hydrogen-bonding capabilities--stemming from its nitrogen and hydrogen constituents--render it a versatile companion to carbon in various advanced material applications [27]. As a result, g-C\({}_{3}\)N\({}_{4}\) plays a prominent role in numerous catalytic processes, including carbon dioxide reduction [28], oxygen reduction reactions (ORRs) [29], hydrogen production from aqueous glycerol solutions [30], and hydrogen evolution reactions [31]. However, the performance of unmodified g-C\({}_{3}\)N\({}_{4}\) is hampered by several inherent limitations such as (i) poor electrical conductivity, (ii) weak interfacial compatibility with other materials, (iii) a limited number of catalytically active sites combined with low Lewis acidity and basicity, and (iv) an inefficient electronic structure that hinders charge transport and reduces its catalytic efficiency [26]. To overcome the inherent drawbacks of pristine g-C\({}_{3}\)N\({}_{4}\), scientists investigated various modification strategies, including elemental-doping and substitution. Non-metal dopants such as boron, oxygen, phosphorus, and sulfur have been included in the support network to boost its physicochemical properties [28; 32; 33]. Additionally, transition metals like iron, manganese, titanium, and nickel have been used to enhance its catalytic performance [34; 35; 36; 37; 38; 39]. Alkaline and alkaline earth metal oxides--including lithium, barium, calcium, and magnesium--have also been introduced into g-C\({}_{3}\)N\({}_{4}\) structures to further boost activity [40; 41; 42]. These modifications collectively aim to refine the material's surface morphology, chemical reactivity, and electronic behavior while also shedding light on the nature and distribution of active catalytic sites. While the application of modified g-C\({}_{3}\)N\({}_{4}\) materials in photocatalytic processes has been extensively studied, their use in catalyzing the transformation of glycerol into glycerol carbonate remains relatively underexplored. [PERSON] et al. [26] analyzed a phosphorus and sulfur co-doped g-C\({}_{3}\)N\({}_{4}\) catalyst (PSCN) using a one-step thermal condensation method and assessed its catalytic activity for converting glycerol and CO\({}_{2}\) into glycerol carbonate. The reaction, undertaken at 210 \({}^{\circ}\)C using acetonitrile as a dehydrating agent, yielded an 85% glycerol conversion with PSCN, significantly higher than the 60% achieved using unmodified g-C\({}_{3}\)N\({}_{4}\) (CNN). In another study, [PERSON] and [PERSON] [43] investigated MgO-supported g-C\({}_{3}\)N\({}_{4}\) catalysts for the transesterification reaction between glycerol and dimethyl carbonate (DMC). The optimal catalyst, with a MgO to g-C\({}_{3}\)N\({}_{4}\) weight ratio of 6:1, delivered a maximum glycerol carbonate yield of 95.47%. This performance was attributed to its strong basicity and favorable conditions, including a reaction temperature of 80 \({}^{\circ}\)C, a 4 h duration, a 3:1 DMC-to-glycerol molar ratio, a 30 mg catalyst dose, and excellent reusability.