Metal Oxide Based Hydroelectric Cell for Electricity Generation by Water Molecule Dissociation without Electrolyte/Acid

Abstract

Never before has electricity been generated out of metal oxides without using any light (UV/IR), acid, or alkali, but it has been achieved by adding a few drops of water on nanoporous metal oxide based Hydroelectric cell (HEC) at room temperature. Electricity generation has been validated and unified for six different metal oxides based on the principle of water dissociation at oxygen deficient nonporous pellet. The presence of oxygen vacancies on the surface of all metal oxide samples has been confirmed by Raman and Photoluminescence spectroscopy techniques. Tin oxide (SnO2) based HEC has delivered maximum power ∼16.6 mW in a 4.48 cm2 cell area with highest current 22.2 mA, approximately 2.075 times higher than reported 8 mA current in ferrite based HEC. Water chemidissociation at metal oxide surface was found to be reinforced predominantly by electronegativity of metal cations and oxygen vacancies on nanoporous surface. Divergent peak current values ranging from 22.2 to 1.1 mA were obtained depending on internal resistance, grain boundary nature, water molecule dissociation capability, and nanopores connectivity in different oxides. Slow diffusion of ions in certain metal oxides due to high impedance of grain boundaries has reduced current as confirmed by dielectric and impedance spectroscopy. Metal oxide HEC provides an ecofriendly, cost-effective, and portable green energy source with almost no running cost.

Harvesting energy via stimuli‐free water/moisture dissociation by mesoporous SnO 2 –based hydroelectric cell and CuO as a pump for atmospheric moisture

“…The absorption spectrum shown in Figure 1D reveals a sharp absorption edge at~340 nm related to the direct band edge transition of SnO 2 . 18,25,26 Here, the strong electrostatic field, generated due to presence of oxygen vacancies 27,28 (existence of oxygen vacancies were confirmed with photoluminescence spectra shown in Figure S1), dissociates the water molecules (as seen in Figure 2B) according to Tauc plot, as shown in the inset of Figure 1D, confirms a direct bandgap of~3.62 eV and is in accordance with earlier report.…”

“…41-0254. [26][27][28] As discussed above, OHoxidized the Al electrode to release the 3e in the system to develop the potential via subsequent H 2 evolution. The presence of small amount of Cl helps the CuO to slowly react with the atmospheric moisture, which latter getting pumped to porous SnO 2, which leads to the formation of Cu (OH) 2 complex.…”

Significance of interface barrier at electrode of hematite hydroelectric cell for generating ecopower by water splitting

“…Novel green energy device hydroelectric cell has been originated as a potential candidate to play pivotal role in this direction without using any solar/UV irradiation/electrolyte, while it uses little water for energy generation . Water molecule dissociates on octahedrally undercoordinated cations and oxygen defects in nanoporous lithium‐substituted magnesium ferrite .…”

“…Environment benign, low cost, easy manufacturing, facile in electricity generation with significantly useful by‐products of hydroelectric cell (HEC) makes it a potential candidate to replace the existing portable green energy sources . Electric power generation using HEC working principle has already been established on six different metal oxides . Replacement of ferrite with metal oxide allows the material synthesis process facile and low cost .…”

“…Due to inherent oxygen‐deficient nature of metal oxides, easy availability, and processing conditions, metal oxide based HECs are far more advantageous over other energy devices. Low formation energy of oxygen vacancy and easy reduction of Sn (IV) to Sn (II) resulted in higher cell current 22.2 mA in SnO 2 HEC, and emf is slightly reduced due to Sn reduction . Versatility of HEC working principle can be further examined on highly active hematite nanostructure owing to the presence of inbuilt oxygen vacant adsorption sites …”