Commercial wearable piezoelectric sensors possess excellent anti-interference stability due to their electronic packaging. However, this packaging renders them barely breathable and compromises human comfort. To address this issue, we develop a PVDF piezoelectric nanoyarns with an ultrahigh strength of 313.3 MPa, weaving them with different yarns to form three-dimensional piezoelectric fabric (3DPF) sensor using the advanced 3D textile technology. The tensile strength (46.0 MPa) of 3DPF exhibits the highest among the reported flexible piezoelectric sensors. The 3DPF features anti-gravity unidirectional liquid transport that allows sweat to move from the inner layer near to the skin to the outer layer in 4 s, resulting in a comfortable and dry environment for the user. It should be noted that sweating does not weaken the piezoelectric properties of 3DPF, but rather enhances. Additionally, the durability and comfortability of 3DPF are similar to those of the commercial cotton T-shirts. This work provides a strategy for developing comfortable flexible wearable electronic devices.

Photocatalytic hydrogen evolution, as an environmental-friendly, energy-saving and simple process, has been widely reported. However, there are some important factors that prohibit practical application of photocatalytic hydrogen production, including the low efficiency of solar energy utilization, and the lack of response in the dark. Temperature fluctuation is a very common phenomenon in our daily life, which is rarely reported for use for hydrogen production. Here we demonstrate direct hydrogen evolution through the harvesting of cold–hot 298–323 K (25–50 °C) alternation energy by using pyroelectric nanomaterial Ba_0.7Sr_0.3TiO₃ (BST). The yield of hydrogen achieved was 46.89 μmol per gram of catalyst after 36 thermal cycles and the rate of hydrogen generation was up to 1.30 μmol g⁻¹ per thermal cycle. The minimum of the conduction band of BST is more negative than the conduction band level of H⁺/H₂, enabling the reduction of water to form hydrogen. This efficient and eco-friendly pyro-catalytic method provides a promising future for hydrogen evolution utilizing natural cold–hot temperature fluctuation energy.

A strong pyro-catalytic dye degradation with an ultrahigh degradation efficiency (>99%) in hydrothermally synthesized pyroelectric BiFeO₃ nanoparticles was achieved under a room-temperature cold–hot alternating excitation (between 27 °C to 38 °C). The pyro-catalysis originated from a combination of the pyroelectric effect and the electrochemical oxidation–reduction reaction. The intermediate products (hydroxyl radicals and superoxide radicals) of pyro-electro-catalysis were observed. Pyro-catalysis provides a highly efficient and reusable dye wastewater decomposition technology through utilizing environmental day–night temperature variation.