Thermal decomposition behaviors of PVP coated on platinum nanoparticles

Abstract

TG-DTA, TEM, and IR were used to investigate the thermal decomposition behavior of poly(N-vinyl-2-pyrrolidone) (PVP). The TG-DTA results show that the thermal decomposition behavior of PVP on platinum (Pt) is quite different from that of pure PVP. For pure PVP, 95.25% is decomposed when the temperature is increased up to 500°C; while under the same experimental condition, PVP coated on the Pt nanoparticles is only 66.7% decomposed. This is further supported by IR measurement. TEM results exhibited that the partially decomposed PVP still plays a role in stabilizing Pt nanoparticles: after heating treatment at 500°C for half an hour, the platinum nanoparticles did not aggregate heavily.

Polyvinylpyrrolidone assisted sol–gel route LiCo1/3Mn1/3Ni1/3PO4 composite cathode for aqueous rechargeable battery

“…In the case of SG, weight loss in this region is high (22%), due to combustion of nitrate ions present in PVP [23]. The second DSC curve indicating the exothermic reaction in SG at 439°C is due to degradation of pyrrolidone ring in PVP [20,24]. The TG curves clearly show that in SG only a trace amount of weight loss (due to slow decomposition of carbon and nitrogen) was found beyond 450°C, however, in SS weight loss was extended till 650°C.…”

“…The decomposed product is expected to be a new organic molecule instead of simple carbon residue that is trapped on the cathode surface. This trapped organic interface between the solid electrode particles and electrolyte increases the electrolyte penetration (lithium ion mobility) and gives improved conductivity [15,20].…”

Olivine-type cathode for rechargeable batteries: Role of chelating agents

“…galvanostatically at a constant current of 0.2 mA (on mass density 8 mA/g) using an 8 channel battery analyzer from MTI Corp., USA, operated by a battery testing system (BTS). extending up to 405°C may be ascribed to the decomposition of CA benzene ring (six carbon atoms) and the formation of the olivine compound, which is displayed by the predominant exothermic peak observed [13,16] in the DSC profile around 400 o C. Small endothermic peak in the region 150 to 250°C for all samples is attributed to the release of physically adsorbed water from the precursor mix and ammonia as by-product [17]. The CA and PVP samples show only the exothermic peaks, whereas TEA sample shows two endothermic peaks at 350°C and 425°C.…”

“…But the degradation of CA during synthesis leave randomly coated residual carbon over the cathode that does not show any superior quality in terms of electrochemical performance to that of the uncoated cathode [11]. In this context, the chelating agents like triethanolamine (TEA) and polyvinylpyrrolidone (PVP) have unique properties [11][12][13]. One of the unique properties of TEA is the presence of nitrogen atoms which act as a fuel in producing internal heat and performs a combustion reaction.…”

“…The resulted heat accelerates remarkably the decomposition of the remaining constituents that results in smaller particle size with higher crystallinity [12]. In the case of PVP, the unique strong pyrrolidine ring (with nitrogen and carbon atoms) in PVP decomposes and forms a new organic trap over the material that increases the conductivity of the olivine [11,13]. Hence, the physicochemical properties of olivine powders strongly depend on the chelating agent used in the sol-gel method.…”