Pyroelectric nanostructures can effectively generate temperature-mediated reactive oxygen species (ROS) through the pyroelectric effect, providing promise for treating hypoxic tumors; and therefore, the synergistic application of photothermal therapy (PTT) and pyroelectric dynamic therapy (PEDT) presents an intriguing approach for cancer therapy. However, this method still faces challenges in improving pyroelectric catalysis and achieving precise tumor localization. In this study, a nano-heterojunction based on CeO2-BaTiO3 nanorods (IR1061@PCBNR) is reported, which exhibits highly effective pyroelectric catalysis for simultaneous tumor-targeted dynamic therapy and gentle photothermal therapy through the utilization of the rich oxygen vacancies. The oxygen vacancies create active sites that facilitate the migration of pyroelectrically-induced charge carriers, improving charge separation and ROS generation. IR1061@PCBNR also demonstrates high tumor penetration; while, minimizing damage to normal cells. This precise nanomedicine strategy holds great potential for advancing dynamic cancer therapies by overcoming the limitations of conventional approaches.

Nanozyme activity is greatly weakened by the microenvironment and multidrug resistance of tumor cells. Hence, a bi-catalytic nanoplatform, which promotes the anti-tumor activity through \"charging empowerment\" and \"mutual complementation\" processes involved in enzymatic and pyroelectric catalysis, by loading ultra-small nanoparticles (USNPs) of pyroelectric ZnSnO3 onto MXene nanozyme (V2CTx nanosheets), is developed. Here, the V2CTx nanosheets exhibit enhanced peroxidase activity by reacting V3+ with H2O2 to generate toxic ·OH, accelerated by the near-infrared (NIR) light mediated heat effect. The resulting V4+ is then converted to V3+ by oxidizing endogenous glutathione (GSH), realizing an enzyme-catalyzed cycle. However, the cycle will lose its persistence once GSH is insufficient; nevertheless, the pyroelectric charges generated by ZnSnO3 USNPs continuously support the V4+/V3+ conversion and ensure nanoenzyme durability. Moreover, the hyperthermia arising from the V2CTx nanosheets by NIR irradiation results in an ideal local temperature gradient for the ZnSnO3 USNPs, giving rise to an excellent pyroelectric catalytic effect by promoting band bending. Furthermore, polarized charges increase the tumor cell membrane permeability and facilitate nanodrug accumulation, thereby resolving the multidrug resistance issue. Thus, the combination of pyroelectric and enzyme catalysis together with the photothermal effect solves the dilemma of nanozymes and improves the antitumor efficiency.

Advanced oxidation processes (AOPs), achieved through the continuous attack of reactive oxygen species (ROS), are considered the most efficient way to mineralize organic pollutants. Among them, photocatalysis is the most environmentally friendly strategy for pollution mitigation but is hampered by low conversion efficiency. By exploiting the coupling effect without changing the properties of the semiconductor, the application of pyroelectric fields can significantly improve the catalytic performance. The degradation rate of rhodamine B by Bi0.5Na0.5TiO3 (BNT) nanoparticles under temperature fluctuations and visible light irradiation was up to 98%. The performance was enhanced by 216.54% and 31.48% compared to the pyroelectric catalysis and photocatalysis alone, respectively. The improved performance is due to the introduced pyroelectric potential with the imposition of temperature fluctuations, which can make the domains enhance the polarization of ferroelectrics, thus promoting the charge separation. This method can significantly advance the coupled pyro-photocatalytic reaction of ferroelectric semiconductors and also can enable the synergistic utilization of multiple energy sources such as solar and thermal energy, which is a promising strategy for environmental remediation.

When it comes to using solar energy to promote catalytic reactions, photocatalysis technology is the first choice. However, sunlight can not only be directly converted into chemical energy through a photocatalytic process, it can also be converted through different energy-transfer pathways. Using sunlight as the energy source, photocatalytic reactions can proceed independently, and can also be coupled with other catalytic technologies to enhance the overall catalytic efficiency. Therefore, sunlight-driven catalytic reactions are diverse, and need to be given a specific definition. We propose a timely perspective for catalytic reactions driven by sunlight and give them a specific definition, namely \"solar energy catalysis\". The concept of different types of solar energy catalysis, such as photocatalysis, photothermal catalysis, solar cell powered electrocatalysis, and pyroelectric catalysis, are highlighted. Finally, their limitations and future research directions are discussed.

Because of the deficiency of lymphatic reflux in the tumor, the retention of tumor interstitial fluid causes aggravation of the tumor interstitial pressure (TIP), which leads to unsatisfactory tumor penetration of nanomedicine. It is the main inducement of tumor recurrence and metastasis. Herein, we design a pyroelectric catalysis-based \"Nano-lymphatic\" to decrease the TIP for enhanced tumor penetration and treatments. It realizes photothermal therapy and decomposition of tumor interstitial fluid under NIR-II laser irradiation after reaching the tumor, which reduces the TIP for enhanced tumor penetration. Simultaneously, reactive oxygen species generated during the pyroelectric catalysis can further damage deep tumor stem cells. The results indicate that the \"Nano-lymphatic\" relieves 52% of TIP, leading to enhanced tumor penetration, which effectively inhibits the tumor proliferation (93.75%) and recurrence. Our finding presents a rational strategy to reduce TIP by pyroelectric catalysis for enhanced tumor penetration and improved treatments, which is of great significance for drug delivery.

A novel catalytic effect of pyroelectric materials induced by a change in temperature, namely pyroelectric catalysis, was found to be attractive due to its ability to utilize waste heat in pollution treatment. In this work, the pyroelectric catalytic properties of BaTiO3 (BTO) nanowires synthesized by a template hydrothermal method have been thoroughly investigated. The nanowires with an elongated polar axis show a superior pyroelectric catalytic performance in comparison with the equiaxial nanoparticles. Our numerical simulation results with a finite element method indicate that the enhanced catalytic efficiency of BTO nanowires can be attributed to the higher pyroelectric potential. On the basis of the pyroelectric effect and our experimental results, a pyroelectric catalytic degradation mechanism has been proposed by taking into account the migration of charge carriers and the formation of reaction radicals. This study for enhancing the pyroelectric catalytic activity by using BTO nanowires may provide a facile, promising, and new reusable strategy for the catalytic degradation of organic dye pollutant by means of temperature variation. It is hoped that the present work gives a clear understanding of the mechanism of pyroelectric catalysis.