It’s odd, but it’s true. The boiling point also drops dramatically. In my 8th grade science class, after using a vacuum pump to cause a one-gallon oil can to be crushed by atmospheric pressure, Mr. King set up another “wow” demo. He put a beaker of water in a bell jar, and he started up the vac pump. Before long the water boiled. Then, because the evaporation was so fast, with no heat applied, ice formed on top of the furiously boiling water! We were all gobsmacked. It was a Mr. Wizard moment.
I assume whast you mean by decelerate the water is slow down the water molocules until they become a solid, in which case it is still acceleration, because acceleration is not inherently positive or negative, it is just a change in velocity.
But on the practical side of this question, if you get a small, battery operated fan and place that so it blows over the ice tray, that will also speed up the freezing process.
Air is a rotten thermal conductor. You might try getting a substance with a very low freezing point, such as ethyl alcohol and making a bath out of it. Pre-cool the bath. Then, insert your ice cube tray into the bath as deeply as possible without getting submerging it.
Liquid water is better thermal conductor than ice. If you can cause the water to supercool (stay liquid below normal freezing temperature) a container of it will end up solid faster than if you allow an ice crust to form on the surface immediatly.
Boiling the water will remove most of the tiny air bubble from it, which form nucleation sites for the formation of ice crystals. if you put the boiling water into a container and let it settle while still hot (no stirring, shaking, etc) it will end up as solid ice sooner than aereated room temperture water.
As others have mentioned air is a poor thermal transfer medium. One type of large ice making machines have flat plate (freon) evaporators that are sprayed with water. Most of the water freezes, and what drips off is recycled. The plates are then stripped, usually by hot-gas bypass of the refrigeration system.
A college prank (Caltech) once performed by a friend of mine involved soaking a matress with water, then slowly pouring a large dewar of liquid nitrogen over it, producing a solidly frozen bed with only 10 minutes or so access to the victim’s dorm room.