41 results about "Reversible hydrogen electrode" patented technology

The invention discloses a method for preparing a porous alpha-Fe2O3 photo-anode and belongs to the technical field of photoelectric water decomposition. The method uses fluorine doped SnO2 conductive glass (FTO) as a substrate, a FeOOH film uniformly grows on an FTO surface through hydrothermal reaction, and then a photo-anode material of an alpha-Fe2O3 film with pores formed in the surface is prepared through microwave assisted heating. The method is simple in operation, mild in reaction condition, short in reaction period and high in repeatability, raw materials are cheap and are easy to obtain, complicated and expensive devices are not needed, the preparation cost is low, the prepared material has excellent oxygen production performance when being applied to photoelectric water decomposition, the photoelectric current density can be up to 2.4 mA/cm<2> under the simulated sunlight irradiation compared with a reversible hydrogen electrode 1.23 V, and the method has wide application prospect on the aspect of development of sustainable clean energy.

A corrosion-resistant electrode catalyst for oxygen reduction includes a main catalyst composed of at least one transition metal oxide selected from oxygen-deficient ZrO₂, Ta₂O₅, Nb₂O₅, TiO₂, V₂O₅, MoO₃, and WO₃ and a co-catalyst composed of gold. The electrode catalyst is used in contact with an acidic electrolyte at a potential at least 0.4 V higher than the reversible hydrogen electrode potential. The catalyst may be used, for example, in such a form that the transition metal oxide in the form of fine particles and gold in the form of fine particles, or fine particles including fine gold particles coated with the transition metal oxide are dispersed on a catalyst carrier which is an electron conductive powder. This electrode catalyst is suitable as an electrode catalyst for an electrochemical system using an acidic electrolyte in the fields of water electrolysis, inorganic/organic electrolysis, fuel cells, etc.

The invention relates to a catalyst for preparing formic acid through efficient electrocatalytic reduction of carbon dioxide and a preparation method thereof, and belongs to the technical field of electrocatalysis. According to the preparation method, SnS2 nanosheets are used as precursors, and the black porous SnO2 nanosheet catalyst for preparing formic acid through efficient electrocatalytic reduction of carbon dioxide is prepared through high-temperature calcination and annealing processes. The method specifically comprises the following steps: (1) preparing a SnS2 nanosheet precursor through chemical vapor deposition; (2) calcining the SnS2 precursor in air to obtain a white porous SnO2 nanosheet; and (3) annealing the white SnO2 nanosheet in a mixed atmosphere of hydrogen and argon to obtain the black porous SnO2 nanosheet. The catalyst for electrocatalytic reduction of carbon dioxide shows excellent performance of preparing formic acid by electrocatalytic reduction of carbon dioxide. Under the overpotential of 0.51 V, the voltage of the capacitor is reduced; the Faraday conversion efficiency of converting carbon dioxide into formic acid reaches 92.4%; the Faraday conversionefficiency of formic acid within the voltage range of -0.60 V to -1.10 V (relative to a reversible hydrogen electrode, RHE) can be stabilized at 90+/-2%; and obtaining a current density of 11.4 +/- 0.3 mA/cm2 and a formic acid Faraday conversion efficiency of 90+/-0.5% at -1.10 V (relative to the reversible hydrogen electrode, RHE) for at least 10 hours.

The present invention belongs to the technical field of electro-catalysis, and especially relates to a preparation method of a Fe/N/C codoped electrocatalyst for efficient oxygen reduction reaction and application of a Fe/N/C codoped electrocatalyst for efficient oxygen reduction reaction. The composition of the Fe/N/C codoped electrocatalyst for efficient oxygen reduction reaction mainly comprises two steps consisting of a hydrothermal reaction step and a high-temperature pyrolysis step. The step 1 is that: carbon black, glucose, sodium dodecyl sulfate and a ferric salt dissolved into secondary water for ultrasonic treatment to form a uniform suspension liquid, and the mixed solution is put into a reaction kettle to perform the hydrothermal reaction to obtain black solid powder, namely aprecursor; and the step 2 is that: the precursor is fully mixed with a nitrogen source in a certain proportion for high-temperature calcinations in a nitrogen atmosphere to obtain a Fe/N/C codoped catalyst. According to the prepared catalyst, it can be seen that the obvious active particles are uniformly doped into a carbon skeleton, a related electrochemical testing result shows that the catalystcan effectively catalyze the oxygen reduction reaction (ORR) in an alkaline medium, the half-wave potential of the Fe/N/C codoped electrocatalyst reaches 821 mV (compared to a reversible hydrogen electrode) which is slightly lower than a commercial Pt/C with 857mV, and the Fe/N/C codoped electrocatalyst has the better stability and methanol tolerance performance than the commercial Pt/C.

An electrochemical reduction device comprises an electrode unit including an electrolyte membrane, a reduction electrode, and an oxygen evolving electrode; a power control unit that applies a voltage Va between the reduction electrode and the oxygen evolving electrode; a hydrogen gas generation rate measurement unit that measures a hydrogen gas generation rate F1; and a control unit that controls the power control unit so as to gradually increase the Va within a range that satisfies a relationship of F1≦F0 and V_CA>V_HER−acceptable potential difference (APD), when the potential at a reversible hydrogen electrode is V_HER, the potential of the reduction electrode is V_CA, the acceptable upper limit of the hydrogen gas generation rate is F0, and the APD is a potential difference that defines an upper limit of a potential difference between V_CA and V_HER.

The invention relates to a ferroelectric composite Cu2O visible light water photolysis hydrogen production photocathode and a preparing method thereof. The photocathode is sequentially composed of a BiFeO3 ferroelectric film layer, a gold nano-rod granular layer, a Cu2O film layer and a silicon wafer substrate from top to bottom, and heterojunctions are formed between the Cu2O film layer and the BiFeO3 ferroelectric film layer. According to the ferroelectric composite Cu2O visible light water photolysis hydrogen production photocathode and the preparing method of the photocathode, adverse effects of energy band barriers between the Cu2O film layer and the BiFeO3 ferroelectric film layer are eliminated through gold nano-rod granules by means of the LSPR effect, absorption of visible light with the wave length ranging from 650 nm-750 nm is strengthened, the Cu2O film layer is protected by the BiFeO3 ferroelectric film layer, residual polarization electric fields are used for eliminatingupwarp barriers on photoelectrode/electrolyte interfaces, the water photolysis efficiency and the hydrogen production efficiency are improved, the light current density reaches 91 microampere/cm<2>, and the threshold voltage relative to a reversible hydrogen electrode reaches 1.01 V.

The present invention relates to an alpha-Fe2O3 photo-anode and a preparation method thereof, the alpha-Fe2O3 photo-anode uses alpha-Fe2O3 as a light absorption layer, and uses Fe3O4, FeO and Fe as a conductive substrate. A direct high temperature fast oxidation method is used to prepare the photo-anode which comprises the conductive substrate and doped or non-doped alpha-Fe2O3, the doped or non-doped alpha-Fe2O3 as a light active layer is closely contacted with the conductive substrate, has good photoelectrocatalytic activity, under the AM1.5 standard test conditions, and relative to the reversible hydrogen electrode 1.23V, 0.63mA / cm2 can be achieved. Unlike publicly reported methods, the raw material of the method is easy to get, the whole photo-anode preparation process is fast, and large scale preparation is easy to realize. The photo-electrode can be used for the use of the decomposition of water for preparation of hydrogen, reduction of carbon dioxide, and the photocatalytic degradation of organic compounds, and the like.

The invention discloses a CuO nanosheet as well as a preparation method and application thereof. CuO nanosheets are prepared from top to bottom, that is to say , CuO with a nano structure is preparedfrom a copper material with a large size through ultrasonic etching and other technologies, and the specific operation method comprises: carrying out oil removal, acid pickling and water washing on the copper raw material, adding the copper raw material into a mixed solution of ammonium persulfate and sodium hydroxide, carrying out ultrasonic treatment, filtering, carrying out centrifugal separation on the filtrate, taking the precipitate, washing and drying to obtain a precursor; and grinding the precursor into powder, heating, and roasting to obtain the CuO nanosheet. The preparation methodprovided by the invention is simple in process and relatively low in cost, and the obtained product is uniform in morphology, good in repeatability and relatively high in electrocatalytic performance.The CuO nanosheet is used as a catalyst for electrocatalytic reduction of carbon dioxide, a reversible hydrogen electrode is used as a standard, the Faraday efficiency of a C<2<+>> product obtained through reduction at-0.97 V exceeds 60%, and high C<2<+>> product selectivity of a CuO electrocatalyst in carbon dioxide reduction is shown.

An electrochemical reduction device includes an electrode unit, a power control unit, an organic material storage tank, a concentration measurement unit, a water storage tank, a gas-water separation unit, and a control unit. The electrode unit includes an electrolyte membrane, a reduction electrode, and an oxygen evolving electrode. The control unit controls the power control unit so as to satisfy a relation of V_HER−V_allow≦V_CA≦V_TRR when the potential at a reversible hydrogen electrode, the standard redox potential of the aromatic compound, and the potential of the reduction electrode are expressed as V_HER, V_TRR, and V_CA, respectively. V_allow is adjusted according to the concentration of the aromatic compound measured by the concentration measurement unit.

The invention belongs to the technical field of electrolysis water catalyzation, and discloses a catalytic oxygen evolution electrode and a preparation method and application thereof. The catalytic oxygen evolution electrode is prepared in a manner that the voltage equivalent to -0.8 V--0.4 V of the voltage of a saturated Ag/AgCl reference electrode is applied in an electrolyte and the constant-pressure treatment time ranges from 30 s to 1800 s. According to the method that the catalytic oxygen evolution electrode can be used for reducing electrolysis water energy consumption, the catalytic activity of a noble metal catalyst (RuO2, IrO2), a metal catalyst (Co3O4) and a double perovskite material PrBa0.5Sr0.5Co1.5Fe0.5O5+alpha nanowire is improved; the treatment method is simple and practicable, and in the electrode preparation process, the shape and size of the electrode can be controlled; and the oxygen evolution performance of the catalytic oxygen evolution electrode prepared by themethod under the voltage ranging from 1 V to 2 V (relative to a reversible hydrogen electrode) is greatly improved, and application prospects are good.

An electrochemical reduction device is provided with an electrode unit, a power control unit, an organic material storage tank, a water storage tank, a gas-liquid separator, and a control unit. The electrode unit has an electrolyte membrane, a reduction electrode, and an oxygen evolving electrode. The electrolyte membrane is formed of an ionomer. A reduction catalyst used for the reduction electrode contains at least one of Pt and Pd. The oxygen evolving electrode contains catalysts of noble metal oxides such as RuO₂, IrO₂, and the like. The control unit controls the power control unit such that a relationship, V_HER−20 mV≦V_CA≦V_TRR, can be satisfied when the potential at a reversible hydrogen electrode, the standard redox potential of an aromatic hydrocarbon compound or an N-containing heterocyclic aromatic compound, and the potential of the reduction electrode are expressed as V_HER, V_TRR, and V_CA, respectively.

A fuel cell electrode catalyst including an active complex including a cerium (Ce)-nitrogen (N) bond and having an oxygen reduction activity of at least 1 milliampere per square centimeter at 0.5 volts versus a reversible hydrogen electrode.

The invention provides a preparation method and application of a nanowire-structured copper/cuprous sulfide/copper mesh electrode material, the method takes a copper mesh as a substrate, cuprous sulfide nanorods grow on the copper mesh substrate by chemical oxidation and gas phase vulcanization methods to obtain an electrode material, and the electrode material is subjected to electrochemical reduction to obtain the nanowire-structured copper/cuprous sulfide/copper mesh electrode material. A copper/cuprous sulfide nanowire/copper mesh electrode is formed, and the surface chemistry is shown as Cu/Cu2S/CM; wherein Cu/Cu2S is of a nanowire net structure. The material is characterized in that the copper/cuprous sulfide nanowires grown on the copper mesh are uniformly distributed, and the copper/cuprous sulfide nanowires have abundant elemental copper and cuprous sulfide interfaces. The electrode material is used for generating ethanol through electrocatalytic reduction of carbon dioxide and has good catalytic performance, and under the overpotential of-0.8 V (vs RHE, relative to a reversible hydrogen electrode), the initial current can reach 12.8-13.5 mA cm <-2 >, the selectivity of ethanol reaches 9.8-13.8%, the yield of ethanol reaches 982.5-987.3 [mu] mol.L <-1 >. H <-1 >, and the double-electric-layer capacitance value of the electrode reaches 19.18-20.50 mF cm <-1 >.

The invention relates to a preparation method and application of a nitrogen and oxygen co-doped carbon material containing 3d metal monatomic, and the method comprises the following steps: mixing ethylenediaminetetraacetic acid or derivatives and hydroxides of ethylenediaminetetraacetic acid and 3d metal salts, calcining at high temperature, centrifugally washing, and drying to obtain the nitrogen and oxygen co-doped carbon material containing 3d metal monatomic. The method is simple and easy to implement, saves energy and is low in cost, the prepared carbon material is uniform in morphology and good in repeatability, the carbon material shows good electro-catalysis performance, when the carbon material serves as an electro-catalyst for producing hydrogen peroxide through oxygen reduction, the electro-catalysis initial potential of the carbon material reaches 0.75 V compared with a reversible hydrogen electrode, the molar selectivity exceeds 95%, and the carbon material has a good application prospect. And the catalyst shows high activity and high selectivity in a reaction for producing hydrogen peroxide through oxygen reduction.

The invention relates to a method for preparing an iron oxide photoanode under the combined action of oxalic acid and tetrabutyl titanate. The method comprises the following steps: carrying out simpleelectrodeposition to obtain an an iron film, soaking the iron film in an oxalic acid (H2C2O4) ethanol solution while heating, carrying out ultrasonic soaking with tetrabutyl titanate (TBT), and carrying out annealing treatment to obtain the Fe2O3-H2C2O4+TBT photoanode. Due to oxalic acid and tetrabutyl titanate, the specific surface area of ferric oxide is increased, electron hole recombination is reduced, and the photoelectric property of ferric oxide is improved. Under AM1.5 standard test conditions, the photocurrent density can reach 0.59 mA cm<2> at 1.23 V relative to a reversible hydrogen electrode. Different from a reported method, the method of the invention has the advantages that raw materials are cheap and easy to obtain, the whole photoelectrode preparation process is fast, andlarge-batch preparation is easy. Different from a conventional method for controlling morphology, the method of the invention is completed by simple impregnation and chemical reaction.

An electrochemical formaldehyde sensor (10) and a method of detecting formaldehyde are disclosed. The electrochemical formaldehyde sensor (10) may comprise a housing (12); an electrolyte disposed within the housing (12); and a plurality of electrodes in contact with the electrolyte within the housing (12), wherein the plurality of electrodes comprise a working electrode (24) comprising iridium andan applied potential of between approximately 0.9 to 1 V relative to a reversible hydrogen electrode; and a counter electrode (16). The cross-sensitivity of the sensor (10) to alcohols is less than approximately 25% of the sensitivity to formaldehyde.