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

Abstract

Hydrogen can contribute significantly to the energy mix of the near future, as it is an attractive replacement for fossil fuels due to its high energy density and low greenhouse gas emission. A fascinating approach is to use the polarization change of a ferroelectric due to an applied stress or temperature change to achieve piezo-or pyro-catalysis for both H 2 generation and wastewater treatment. We exploit low Curie temperature (T c ) ferroelectrics for polarization-driven electrochemical reactions, where the large changes in polarization and high activity of a ferroelectric near its T c provides a novel avenue for such materials. We present experimental evidence for enhanced water splitting and rhodamine B degradation via piezo-catalysis by ultrasonic excitation at its T c . Such work provides an effective strategy for water splitting/treatment systems that employ low T c ferroelectrics under the action of mechanical stress or/and thermal fluctuations.

Polarisation tuneable piezo-catalytic activity of Nb-doped PZT with low Curie temperature for efficient CO2 reduction and H2 generation

“…In addition, the highest and most distinct sono-piezo-catalytic hydrogen and CO production were observed at a working temperature of 38 o C, which correlates with the T c of PZTN, as shown in Figure 3B. It has previously been discussed that pyro-catalytic H 2 generation activity is greatest near the T c [22], and this work demonstrates that is also applied to CO production. By optimization of the piezo-catalytic effect of PZTN in relation to its T C and in the presence of ultrasound, a promising piezo-catalytic CO 2 reduction rate of 789 µmol/g/h is achieved, which is much larger than the those obtained from the pyro-catalytic effect using Bi 2 WO 6 (16.5 µmol/g/h) [35].…”

“…and ~ 1.23 V[78], respectively. While it is difficult to measure the local surface potential of the single piezoelectric particle during the ultrasound, our recent work[22] has demonstrated that the barium strontium titanate (Ba 0.75 Sr 0.25 TiO 3 ) with the comparable ferroelectric polarisation has the ability to split the water for the H 2 generation with the application of ultrasound. The piezoelectric potential can be estimate by…”

Superflexible and Lead-Free Piezoelectric Nanogenerator as a Highly Sensitive Self-Powered Sensor for Human Motion Monitoring

“…c Working mechanism of BTS-GFF/PVDF sensors. d Effect of T c on polarization [ 39 ] and electric responses of sensors under different working temperature …”

“…When the force is released, the internal electric field disappears, resulting in a smaller reverse current [ 34 ]. When the working temperature of the sensor is close to the T c, the internal spontaneous polarization of the films is more likely to rotate under the action of external force [ 39 ], resulting in more induced charges and larger output signal (Fig. 3 d).…”

“…It is well known that the sensors based on hard ceramics will lose piezoelectricity due to the depolarization phenomenon once the work temperature is higher than T c . However, flexible piezoelectric nanogenerators can generate enough electric signals even without poling process and the low T c would be a benefit for flexible sensors because a small alteration of force will trigger large changes in polarization [ 39 ]. Considering about the above facts, flexible BTS materials may have immense potential applications in wearable devices.…”