R.C. Kainthla

Production of tritium from D2O electrolysis at a palladium cathode

In the present communication, we report data that may be relevant to the phenomenon of room temperature fusion [1]. It is the contention of the authors that the alleged phenomenon is better characterized by the production of nuclear particles than by the measurement of bursts of heat. Here, we describe the observation of tritium produced in eleven D2O electrolysis cells at levels 10-10 times above that expected from the normal isotopic enrichment of electrolysis. Particular attention has been paid to possible sources of contamination.

Significant Efficiency Increase in Self‐Driven Photoelectrochemical Cell for Water Photoelectrolysis

A theory relating the electrochemical and solid-state properties of semiconductors to their photoelectrochemical behavior has been used to predict the electrodes that, when combined, will give the optimum efficiencies for the splitting of water by means of solar light to hydrogen and oxygen. This paper represents the first application of this theory. A p-type indium phosphide electrode has been decorated with platinum and combined with an n-type gallium arsenide electrode which has been protected against photocorrosion by depositing a thin film of Mn-oxide on it. Examination has been made of the individual photoelectrochemical behavior of these electrodes in aqueous solution. The I-V curves of these electrodes indicated that, when placed together in a cell, they would spontaneously give rise to hydrogen and oxygen when photoirradiated. X-ray photoelectron spectroscopic examination of the protected gallium arsenide electrode showed no indication of the substrate, i.e., the Mn-oxide completely covered the gallium arsenide.

Photoelectrolysis of H2S using an n-CdSe photoanode

Abstract A photoelectrochemical cell which makes use of chemically deposited thin CdSe film as photoanode and Pt as cathode has been fabricated to photoelectrolyze H 2 S to produce hydrogen. The cell converts light to stored chemical energy at 1.5% conversion efficiency and can also be used to convert light to stored chemical energy and electricity simultaneously. Under the conditions of co-withdrawal the maximum conversion efficiency is 2.85%. The cell showed 97% current conversion efficiency to hydrogen. If the hydrogen produced in the photoelectrochemical cell is used in a H 2 /air fuel cell for electricity generation, practical efficiency of 10.6% can be achieved. The cell has shown good stability for a time period of more than two weeks.

Eight chemical explanations of the Fleischmann-Pons effect

Abstract Eight possible explanations for the heat produced in the Fleischmann-Pons effect are examined with the various conservative assumptions concerning the quantities used. No individual explanation is sufficient to explain the heat produced. All of them together can only explain heat as much as 3 W cm −3 .

The theory of electrode matching in photoelectrochemical cells for the production of hydrogen

Abstract The problem of matching the properties of the semiconductors in a two photon photoelectrochemical cell is addressed. The effect of the semiconductor properties on the performance of the whole cell has been calculated for the first time. Calculations of the cell potential and photocurrent have been made for the first time. Computations have been made for specific combinations of electrodes, e.g., n-SrTiO 3 /p-GaP and n-TiO 2 /p-GaP. Taking different p-type semiconductors as photocathodes, calculations have been made to determine the properties of n-type semiconductors which would be expected to form efficient (>10%) light driven PECs for producing hydrogen. It was found that without electrocatalysts, no combination of oxide semiconductors will give efficiency >4.0%. However, when the effects of the deposition of submonolayer amounts of different electrocatalysts on both the semiconductor surfaces are taken into consideration, the predicted efficiencies of the conversion of light to chemical energy improve substantially. Successful n-type electrodes cannot be oxides and therefore need protective coatings. Calculations suggest that it should be possible to attain efficiency for the conversion of light up to 16% with p-InP (Pt)/n-GaAs(e) and up to 14% with p-Si (Pt)/n-InP (e), using appropriate electrocatalysts on the n-Si and on the n-InP electrodes, together with Mn-oxide protective coating.

The conversion of light and water to hydrogen and electric power

The effect of etching the electrode surface and of the deposition of submonolayer quantities of metal on the semiconductor electrode surface has been examined. The experimental observations show that the rate of reaction (H2 evolution) is determined by the charge transfer rate across the metal-solution interface. Recent experiments also show that the photocorrosion of small band gap non-oxide semiconductor photoanodes can be prevented by depositing suitable conducting transparent coatings on the electrode surface. By using the electrocatalysed photocathodes and protected photoanodes, high efficiencies for the photoelectrolysis of water can be achieved.

An impedance study of the silicon—solution interface under illumination

Abstract Surface states at the semiconductor—electrolyte interface under illumination have been determined. The Faradaic reaction involved at the interface is the hydrogen evolution. An equivalent circuit is proposed which is chosen as giving the best fit to the impedance data among six possible arrangements consistent with present models of the interface. Surface states act as recombination centers decreasing the Faradaic efficiency for the hydrogen evolution reaction. Surface state density at a given bias potential has been calculated to be ≈ 10 12 cm −2 . Adsorbed ions induce surface states. Helmholtz double layer resistance is larger than the space charge resistance in the Tafel region; hence, the rate determining step for hydrogen evolution on Si lies in the double layer region.

Electrochemical fusion: a mechanism speculation

where M, is the rest mass of the deuteron and E is the energy of an adsorbed deuteron incident on the electrode surface after passage from the solution. Let it be supposed that fusion occurs at surface states associated with dendritic protrusions on the electrode surface. It seems reasonable to assume that there is a Volmer-Heyrovsky pathway for deuterium evolution on palladium surfaces at high current density (i). Then, the electrode surface is fully covered with D and the rate of D-D collision (mol cmp2 s-‘) would be i/F (F is the Faraday constant). Should a certain fraction (I) of sites on the electrode surface be sites of abnormally strength, where the energy of the D-D collision is rate at which the D-D barrier is penetrated:

On electrochemical tritium production

This paper reports tritium formed in LiOD-D2O solutions in which Pd cathodes are used to evolve D2. Electrolysis was carried out for up to 412 months. Excess heat has been observed from 5 electrodes out of 28, tritium in 15 out of 53 but 9 out of 13 if the electrodes are limited to 1 mm diameter. Steady state tritium concentrations were 104–107 disintegrations min−1 ml−1. A weak correlation may exist between heat observed and tritium produced. The rate of production of tritium was ca 1010 atoms cm−2 s−1. The branching ratio of tritium to neutrons was ∼108. A theoretical dendrite enhanced fusion model is suggested. Growing gas layer breakdown occurs at sufficiently high surface potential dendrite tips and correspondingly fusion reactions occur. The model gives quantitative consistence with experiment, especially the sporadic nature and the observed branching ratio.

A model of photon-induced self-driven electrochemical cell for water splitting to hydrogen

Abstract An equation for cell current in a self-driven photon-induced electrochemical cell, having both electrodes as semiconducting photoelectrodes, has been derived and applied to water splitting to hydrogen. The cell current and the cell potential depend on various semiconductor properties and the properties of the ions in solution. The computed dependence of cell current and potential for specific combinations of electrodes, e.g. nSrTiO 3 /p-GaP and nTiO 2 /p-GaP, show the same trends as the experimental observation. Further calculations suggest that it should be possible to attain an efficiency of conversion of light up to 18% for water splitting to hydrogen with p-InP (Pt-electrocatalyst)/n-Si (electrocatalyst) and up to 17% with p-Si (Pt)/n-InP(c) using appropriate electrocatalyst on the nSi and on the nInP electrodes.