No, it is not possible to contain electrons inside a vacuum container made of a negatively charged surface alone. Electrons are negatively charged particles, and they repel each other due to their like charges. If a negatively charged surface is used to create an electric field, it can attract and confine positively charged particles, such as ions, but it cannot confine electrons effectively.
Electrons are highly mobile and can easily move through a vacuum or conductive materials. They will tend to repel each other and disperse rather than remain confined within a region defined solely by a negatively charged surface. To effectively contain electrons, additional methods, such as electromagnetic fields or physical barriers, are required.