Photothermally Enabled Pyro-Catalysis of a BaTiO₃ Nanoparticle Composite Membrane at the Liquid/Air Interface

Abstract

This paper reports the highly efficient pyroelectric nanomaterial-based catalytic degradation of waste dye under rapid temperature oscillation, which was achieved by periodical solar irradiation on a porous pyroelectric membrane that was floating at the liquid/air interface. Such a membrane consists of the light-to-heat conversion carbon black film as the top layer and the porous poly(vinylidene difluoride) (PVDF) film embedded with pyroelectric barium titanate (BaTiO) nanoparticles (BTO NPs) as the bottom layer. By using an optical chopper, solar light can be modulated to periodically irradiate on the floating membrane. Because of the photothermal effect and low thermal conductivity of the PVDF polymer, the generated heat is localized at the surface of the membrane and substantially increases the surface temperature within a short period of time. When the solar light is blocked by the chopper, interfacial evaporation through the porous membrane along with convective air cooling and radiative cooling leads to heat dissipation, and then the temperature of the membrane is rapidly decreased. Such an efficient thermal cycle results in a substantial rate of temperature change of the membrane, which enhances its pyroelectric capability and subsequent pyro-catalysis. In contrast, the efficiency of pyro-catalysis through the dispersed BTO NP solution is about 4 times lower than that of the BTO composite membrane. With the large heat capacity of the aqueous solution and inevitable thermal loss because of bulk heating, the rate of temperature change of the BTO NP solution is much smaller than that of the BTO composite membrane and thus results in a relatively small pyro-catalytic capability. Furthermore, the reusability and transferability of this newly developed composite membrane make it amenable to practical use in treating contaminated water. The findings in our report not only offer a new design strategy for efficient solar-enabled pyro-catalysis but also pave a new way to rationally harvest solar-thermal energy in nature for various applications that involve pyroelectric materials.

Demonstration of Enhanced Piezo-Catalysis for Hydrogen Generation and Water Treatment at the Ferroelectric Curie Temperature

“…As a model ferroelectric material, barium titanate has often been explored for tribo- (Li et al, 2019), piezo- (Belitz et al, 2017;Feng et al, 2019;Hong et al, 2010, ll OPEN ACCESS 2012;Jin et al, 2019;Pan et al, 2019;Wu et al, 2018a), and pyroelectric catalysis (Benke et al, 2015;Xia et al, 2017). This is primarily due to its lead-free nature, low-cost, and ease of manufacture in a wide variety of forms, such as nanofibers (Wu et al, 2018a;Xia et al, 2017), composites (Min et al, 2018), and particles (Belitz et al, 2017), which can be decorated with semiconductors to enhance catalytic performance.…”

Liquid‐phase preparation of BaTiO3nanoparticles

“… Transmission electron microscope (TEM) photographs of the particle synthesised at 80°C (a) Ba‐ion concentration of 0.1 mol/L, (b) Ba‐ion concentration of 0.58 mol/L [22]…”

“…Presently, the preparation methods of BT nanoparticles mainly include gas-phase method, solid-phase method and liquid-phase method [18][19][20][21][22]. The gas-phase method is classified into a chemical vapour deposition method and a physical vapour deposition method depending on whether or not a chemical reaction occurring.…”

Pyroelectric Synthesis of the Site‐Specific Au‐ZnO Nanorod Array

“…In the pyroelectric process, the spontaneous polarization (P s ) intensity of some crystals with polar point symmetry changes along with the variation of the ambient temperature [25] . The temperature fluctuation will induce the generation of the excess compensation charges on the surface of the pyroelectric material, which subsequently participate in the redox reaction with the surface‐absorbed species [26] . In our previous work, barium titanate (BTO) NPs were adopted as the pyroelectric catalyst in the synthesis of noble metal‐semiconductor hybrid nanomaterials [23] .…”