The role of guanidine hydrochloride in graphitic carbon nitride synthesis

Abstract

Graphitic carbon nitride (CN) was synthesized from guanidine hydrochloride (G), melamine (M) and dicyandiamide (DCDA). The CN materials synthetized from the pure precursors and their mixtures were characterized by common methods, including thermal analysis, and their photocatalytic activities were tested by the degradation of selected organic pollutants, such as amoxicillin, phenol, Rhodamine B (RhB). Remarkable changes in their texture properties in terms of particle sizes, specific surface areas (SSA) and consequently their photocatalytic activity were explained by the role of guanidine hydrochloride in their synthesis. The SSA increased due to the release of NH3 and HCl and its complex reactions with melamine and DCDA forming structure imperfections and disruptions. The photocatalytic activity of the CN materials was found to be dependent on their SSA.

A graphitic carbon nitride-coated quartz crystal microbalance gas sensor for H2 detection

“…1(e), the BET surface area was determined to be 3.0 m 2 g À1 , which was slightly lower than the previously reported value (i.e., B8.0 m 2 g À1 ). 31,32 This low surface area may be due to the aggregation observed in the FESEM image (Fig. 1(d)).…”

“…, ∼8.0 m 2 g −1 ). 31,32 This low surface area may be due to the aggregation observed in the FESEM image (Fig. 1(d)).…”

Interactions Balancing Competition and Cooperation between Covalent–Organic Framework Additives and PEG Base Oil toward Advanced Lubrication

“…As for Ton-COFs, such excellent behavior is due to two units of Ton-COFs being directly bound in C−N covalent bonds, similar to guanidine, whereas oxygen atom bridges two triazine rings in Tol-COFs, forming the carbamimidate structure that generally takes on poor heat tolerance. 28,29 UV−vis adsorption spectroscopy shows that Ton-COFs (ginger line) present a strong adsorption peak at 202.3 nm coupling with a minor one at 219.2 nm, corresponding to n−π* electron transition of carbonyl groups and π−π* electron transition of triazine ring. 30 For Tol-COFs (green line), the existence of a peak at 202.3 nm indicates that a small part of the structural skeleton is equivalent to Ton-COFs, which is in good line with the observation of XRD.…”

“…Based on the TGA curves of both COFs, it can be seen clearly that Ton-COFs display a tough resistance to decomposition than Tol-COFs, which endows Ton-COFs more durable lubrication stability because the friction sliding releases lots of heat that can undermine the lubricant film or even serve as a potential candidate for high-temperature lubricant additive. As for Ton-COFs, such excellent behavior is due to two units of Ton-COFs being directly bound in C–N covalent bonds, similar to guanidine, whereas oxygen atom bridges two triazine rings in Tol-COFs, forming the carbamimidate structure that generally takes on poor heat tolerance. , UV–vis adsorption spectroscopy shows that Ton-COFs (ginger line) present a strong adsorption peak at 202.3 nm coupling with a minor one at 219.2 nm, corresponding to n –π* electron transition of carbonyl groups and π–π* electron transition of triazine ring . For Tol-COFs (green line), the existence of a peak at 202.3 nm indicates that a small part of the structural skeleton is equivalent to Ton-COFs, which is in good line with the observation of XRD.…”

Accelerating NADH oxidation and hydrogen production with mid-gap states of nitrogen-rich carbon nitride photocatalyst

“… 14 For instance, surface engineering of π-conjugative carbon nitride framework with additional organic molecules dramatically alters its optoelectronic properties. 15 , 16 As a result, a new electronic configuration is imparted within the band gap known as the mid-gap/defect state. 17 These intrinsic trap states can potentially reduce radiative charge carrier recombination and thus extend the overall visible light absorption range.…”