Synthesis and Photothermal Properties of UV-Plasmonic Group IV Transition Metal Carbide Nanoparticles

Abstract

Refractory nanostructures can be low-cost and chemically and thermally robust alternatives to metal-based plasmonic materials. While transition metal nitrides have received much attention recently, there has been less emphasis on their closely related non-layered carbide counterparts. In this work, plasmonic group IV transition metal carbide (TiC, ZrC, and HfC) nanostructures were prepared using a facile magnesiothermic reduction method, which yielded a phase pure product. TiC, ZrC, and HfC with rock salt crystal structures and an average particle size of 24, 31, and 42 nm, respectively, were obtained by reacting corresponding metal oxide, magnesium, and biochar in the solid state. Calculations performed using a finite element method predicted these group IV carbide nanostructures to have localized surface plasmon resonance in the UV region between 150 and 175 nm. The photothermal transduction efficiency of each carbide was explored to further verify the plasmonic behavior. HfC was found to have the highest photothermal transduction efficiency of 73%, followed by ZrC (69%), and then TiC (60%) at 365 nm.

Plasmonic group IV transition metal carbide interfaces for solar-driven desalination

“…The SEM images of the MCE filters with 1.0 g m -2 loading of the carbides (Figure 1A) showed that some degree of porosity is still retained after the coating. The TMC dispersions displayed absorbance maxima deep in the UV region (<200nm) as previously reported (Figure 1B), 57 and the absorbance of all three carbides approached zero at 800 nm. However, when loaded onto the MCE support, the absorbance broadened significantly.…”

“…Plasmonic group IV transition metal carbides (TMCs), TiC, ZrC, and HfC were prepared using a previously reported solid state procedure. 57 The metal oxide nanopowder (TiO2, ZrO2, or HfO2) was reacted with birch-residue derived biochar and magnesium powder under argon atmosphere between 950 and 1100° C to yield corresponding carbides (TiC, ZrC, HfC). The biochar was synthesized via a reported pyrolysis method.…”

“…Detailed analyses done in a previous study have shown these nanoparticles also posses an amorphous oxide/oxycarbide shell around the crystalline carbide core. 57 To prepare the evaporation interface, a 1.0 mg mL -1 dispersion of a given TMC was dropcast onto a 2.5 cm diameter mixed cellulose ester (MCE) filter paper (0.45µm pore size) under vacuum to reach loadings of 0.5, 1.0, 1.5, and 2.0 g m -2 . The SEM images of the MCE filters with 1.0 g m -2 loading of the carbides (Figure 1A) showed that some degree of porosity is still retained after the coating.…”

“…This led to average light absorption of 82% (ZrC), 86% (TiC), and 95% (HfC) between 300 and 1500 nm (Figure 1C). This broadband absorption likely originates from increased coupling of the plasmonic particles with one another while in close proximity on the MCE support 30,57,59 and could be further enhanced by light trapping within the pores. [60][61][62] The plasmonic TMC coated MCE filters were placed on top of a 0.5-inch EVA foam support with one dimensional cotton fabric wicks (Figure 1D).…”

“…53,54 Our group and others have shown the utility of plasmonic nitrides for solar-driven desalination. 42,55,56 Similar to the nitrides, plasmonic group IV non-MXene carbides also exhibit strong photothermal properties, 57 however, they are relatively a newcomer in the field and haven't been widely explored. Recently, commercially purchased ZrC were used to develop a carbide solar-driven evaporator by Liu et al 35 which showed evaporation rate and efficiency of 1.38 kg m −2 h −1 and 96%, respectively, under 1 sun illumination at a mass loading of 85 g m -2 .…”