Methods and systems related to the field of carbon capture and utilization are disclosed. Disclosed electrolysis reactors can have a cathode area having a cathode output and a cathode input for an input fluid and an anode area having an anode input and an anode output. The carbon input fluid contains carbon dioxide. The cathode area reduces an oxygen-containing species into hydroxide ions and reacts them with the carbon dioxide to form anions containing carbon. The anode area oxidizes one or more oxidizable species to generate a protonating species. The electrolysis reactors can have a third output for a carbon output fluid. The electrolysis reactors can begin to produce carbon dioxide from the anions containing carbon and the protonating species in response to a potential of less than 1.23 V applied across the cathode terminal and the anode terminal.

During electro-oxidative metal removal on a semiconductor substrate, the substrate having a metal layer is anodically biased and the metal is electrochemically dissolved into an electrolyte. Metal particles (e.g., copper particles when the dissolved metal is copper) can inadvertently form on the surface of the substrate during electrochemical metal removal and cause defects during subsequent semiconductor processing. Contamination with such particles can be mitigated by preventing particle formation and/or by dissolution of particles. In one implementation, mitigation involves using an electrolyte that includes an oxidizer, such as hydrogen peroxide, during the electrochemical metal removal. An electrochemical metal removal apparatus in one embodiment has a conduit for introducing an oxidizer to the electrolyte and a sensor for monitoring the concentration of the oxidizer in the electrolyte.

Disclosed herein are methods and systems that relate to oxidizing a metal ion of a metal oxyanion or a non-metal ion of a non-metal oxyanion from a lower oxidation state to a higher oxidation state at an anode and generate hydrogen gas at the cathode. The metal oxyanion with the metal ion in the higher oxidation state or the non-metal oxyanion with the non-metal ion in the higher oxidation state may be then subjected to a thermal reaction or a second electrochemical reaction, to form oxygen gas as well as to regenerate the metal oxyanion with the metal ion in the lower oxidation state or the non-metal oxyanion with the non-metal ion in the lower oxidation state, respectively.

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn.sup.2+) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn.sup.4+) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10° C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10° C. or lower, and the stannous oxide powder is dissolved.

The present invention provides a high-concentration tin sulfonate aqueous solution, in which a divalent tin ion (Sn.sup.2+) concentration is 360 g/L to 420 g/L, a tetravalent tin ion (Sn.sup.4+) concentration is 10 g/L or less, a free methanesulfonic acid concentration is 40 g/L or less, a Hazen unit color number (APHA) is 240 or less, and a turbidity is 25 FTU or less. This aqueous solution is produced such that stannous oxide powder whose temperature is adjusted to a temperature of 10° C. or lower is added to an aqueous methanesulfonic acid solution having a concentration of 60% by mass to 90% by mass when the aqueous solution circulates in a state of being maintained at the temperature of 10° C. or lower, and the stannous oxide powder is dissolved.

Herein discussed is a method of producing hydrogen comprising introducing a first stream comprising a fuel to an electrochemical (EC) reactor having a mixed-conducting membrane, introducing a second stream comprising water to the reactor, reducing the water in the second stream to produce hydrogen, and recycling at least portion of the produced hydrogen to the first stream, wherein the membrane comprises an electronically conducting phase and an ionically conducting phase; and wherein the first stream and the second stream do not come in contact with each other in the reactor.

Provided is a method for preparing copper azide and cuprous azide encapsulated by conductive metal-organic framework. The method uses a conductive copper-containing metal-organic framework material as a precursor, and completes the azidation of the precursor by means of a liquid-solid electrochemical azidation reaction. Copper azide and cuprous azide nanocrystals are highly uniformly embedded within a conductive framework, which may effectively avoid the agglomeration of copper azide and cuprous azide, and reduce static charge generated by friction, displacement, and the like. Meanwhile, the conductive framework may promote the effective transfer of charge, avoid the accumulation of static charge, and improve the electrostatic safety. In addition, the liquid-solid electrochemical azidation reaction has advantages such as being safe and efficient, having a short reaction time and having strong operability, and the preparation process is compatible with a MEMS process, which is beneficial for the application of copper azide and cuprous azide materials in micro devices.

An apparatus for storing hydrogen as protons and electrons separately. The apparatus includes a DC power supply; a hydrogen electrolysis unit including a hydrogen tank adapted to contain hydrogen under pressure and in contact with one or more catalyst electrodes contained in the tank, the one or more catalyst electrodes in electrical connection with the DC power supply; and an electron storage unit for storing electrons, the electron storage unit in electrical connection with the DC power supply and separated from the hydrogen electrolysis unit. In a proton generation mode, the DC power supply is configured to operate the one or more catalyst electrodes in anode mode to catalyze oxidation of hydrogen in the hydrogen tank to form and store protons on or near the one or more electrodes and store generated electrons in the electron storage unit.

In some aspects, the present disclosure pertains to methods for the electrochemical production of calcium silicate compounds in an electrochemical cell that comprises (a) a Ca-based electrode that comprises calcium metal or an inorganic calcium material, (b) an SiO.sub.x-based electrode that comprises a SiO.sub.x material, where x ranges from 1 to 2, and (c) a liquid electrolyte disposed between the Ca-based electrode and the SiO.sub.x-based electrode. In these methods, the electrochemical cell is operated under conditions such that calcium cations are produced at the Ca-based electrode and one or more calcium silicate (Ca—Si-oxide) compounds are produced at the SiO.sub.x-based electrode. In other aspects, the present disclosure pertains to systems for the electrochemical production of calcium silicate compounds.

Methods and systems for producing are disclosed. A method for producing iron, for example, comprises: providing an iron-containing ore to a dissolution subsystem comprising a first electrochemical cell; wherein the first anolyte has a different composition than the first catholyte; dissolving at least a portion of the iron-containing ore using an acid to form an acidic iron-salt solution having dissolved first Fe.sup.3+ ions; providing at least a portion of the acidic iron-salt solution to the first cathodic chamber; first electrochemically reducing said first Fe.sup.3+ ions in the first catholyte to form Fe.sup.2+ ions; transferring the formed Fe.sup.2+ ions from the dissolution subsystem to an iron-plating subsystem having a second electrochemical cell; second electrochemically reducing a first portion of the transferred formed Fe.sup.2+ ions to Fe metal at a second cathode of the second electrochemical cell; and removing the Fe metal.