电催化:为实现电子化学未来的前景和作用

In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...

Electrochemistry is the branch of chemistry that studies the relationship between electrical quantities and chemical reactions, particularly oxidation and reduction. Oxidation is the loss of electrons from a substance, whereas reduction refers to the gain of electrons. A substance with a strong electron affinity is called an oxidizing agent (oxidant), and a reducing agent (reductant) is a species that donates electrons. Oxidation and reduction processes are pivotal to electrochemical reactions,...

Electricity is generated by either electrons or ions flowing through a solution or a conducting medium. This flow of electrons or specifically electrical charge is defined as an electric current. When electrons move through a wire, they generate an electric current. It can be recalled  that in a redox reaction, electrons are lost and gained. In the spontaneous redox reaction of zinc  with copper, when zinc is immersed in a copper ion solution, a transfer of electrons from one...

On comparing the reactivity of silver and lead, it is observed that the two ionic species, Ag+ (aq) and Pb2+ (aq), show a difference in their redox reactivity towards copper: the silver ion undergoes spontaneous reduction, while the lead ion does not. This relative redox activity can be easily quantified in electrochemical cells by a property called cell potential. This property is commonly known as cell voltage in electrochemistry, and it is a measure of the energy which accompanies the charge...

 Electrochemical measurements are conducted in an electrochemical cell composed of various components that control and measure the current and potential. One fundamental component is electrodes, conductive materials that enable electron transfer reactions at their surfaces.
There are two main types of electrodes in electrochemical cells. The first type, known as the working or indicator electrode, has a potential that is sensitive to the analyte's concentration and reacts to changes in...

Spontaneous Chemical Reactions
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...