Photoassisted salt-concentration-biased electricity generation using cation-selective porphyrin-based nanochannels membrane

Natural sunlight is one kind of renewable energy that is considered likely to be ubiquitous at the river-sea junction. Ingeniously engineering a photoassisted enhanced electricity capture facility based on an artificial nano-porous membrane, is a necessity. Herein, a proof-of-concept system is constructed, wherein cation-selective photoresponsive porphyrin/alumina nanochannels are entrusted with cationic selectivity and extraordinary photoelectric response, thus it is available to synergistically convert salinity gradient and solar energy into high electric energy. Depending solely on excellent cationic selectivity of nanochannels, the salinity-gradient-driven membrane system can capture high power output of 2.16 W/m². And harvested power of the generator with the help of photo is elevated to 4.56 W/m². Resulted total transmembrane ionic current (I_total) is traceable to a smooth cooperative effort of diffusion current (I_diff) and photo-induced ionic current (I_photo). Benefiting from the accumulation characters of ionic current, the electricity generator with the modulation of concentration gradient and varying-intensity photo stimulus can achieve a multivalued conduction including current and power increase. The general nanofluidic system paves the way for other multi-functional membranes that simultaneously utilize various clean sources to potentially improve entire electricity output.